Tunable Diode Laser Absorption Studies of Hydrocarbons in RF Plasmas Containing Hexamethyldisiloxane

Tunable infrared diode laser absorption spectroscopy has been used to detect the methyl radical and three stable molecules, CH₄, C₂H₂ and C₂H₆, in radio frequency plasmas (f=13.56 MHz) containing hexamethyldisiloxane (HMDSO). The methyl radical concentration and the concentration of the stable hydrocarbons, produced in the plasma, have been measured in pure HMDSO discharges and with admixtures of Ar, while discharge power (P=20–200 W), total gas pressure (p=0.08–0.6 mbar), gas mixture and total gas flow rate (=1–10 sccm) were varied. The methyl radical concentration was found to be in the range of 10¹³ molecules cm^-3, while methane and ethane are the dominant hydrocarbons with concentrations of 10¹⁴–10¹⁵ mol cm^-3. Conversion rates to the measured stable hydrocarbons (RC(C_xH_y): 2×10¹²–2×10¹⁶ molecules J^-1 s^-1) could be estimated in dependence on power, flow, mixture and pressure. Under the used experimental conditions a maximum deposition rate of polymer layers of about 400 nm min^-1 has been found.     

Conversion of natural gas to C2 hydrocarbons through dielectric-barrier discharge plasma catalysis

The experiments are carried out in the system of continuous flow reactors with dielectric-barrier discharge (DBD) for studies on the conversion of natural gas to C₂ hydrocarbons through plasma catalysis under the atmosphere pressure and room temperature. The influence of discharge frequency, structure of electrode, discharge voltage, number of electrode, ratio of H₂/CH₄, flow rate and catalyst on conversion of methane and selectivity of C₂ hydrocarbons are investigated. At the same time, the reaction process is investigated. Higher conversion of methane and selectivity of C₂ hydrocarbons are achieved and deposited carbons are eliminated by proper choice of parameters. The appropriate operation parameters in dielectric-barrier discharge plasma field are that the supply voltage is 20–40 kV (8.4–40 W), the frequency of power supply is 20 kHz, the structure of (b) electrode is suitable, and the flow of methane is 20–60 mL · min⁻¹. The conversion of methane can reach 45%, the selectivity of C₂ hydrocarbons is 76%, and the total selectivity of C₂ hydrocarbons and C₃ hydrocarbons is nearly 100%. The conversion of methane increases with the increase of voltage and decreases with the flow of methane increase; the selectivity of C₂ hydrocarbons decreases with the increase of voltage and increases with the flow of methane increase. The selectivity of C₂ hydrocarbons is improved with catalyst for conversion of natural gas to C₂ hydrocarbons in plasma field. Methane molecule collision with radicals is mainly responsible for product formation.     

Effect of sodium cation on the electrochemical reduction of CO<Subscript>2</Subscript> at a copper electrode in methanol

The electrochemical reduction of CO₂ with a Cu electrode in methanol was investigated with sodium hydroxide supporting salt. A divided H-type cell was employed; the supporting electrolytes were 80 mmol dm⁻³ sodium hydroxide in methanol (catholyte) and 300 mmol dm⁻³ potassium hydroxide in methanol (anolyte). The main products from CO₂ were methane, ethylene, carbon monoxide, and formic acid. The maximum current efficiency for hydrocarbons (methane and ethylene) was 80.6%, at −4.0 V vs Ag/AgCl, saturated KCl. The ratio of current efficiency for methane/ethylene, r _f(CH₄)/r _f(C₂H₄), was similar to those obtained in LiOH/methanol-based electrolyte and larger relative to those in methanol using KOH, RbOH, and CsOH supporting salts. In NaOH/methanol-based electrolyte, the efficiency of hydrogen formation, a competing reaction of CO₂ reduction, was suppressed to below 4%. The electrochemical CO₂ reduction to methane may be able to proceed efficiently in a hydrophilic environment near the electrode surface provided by sodium cation.     

Modeling of H2 and H2/CH4 Moderate-Pressure Microwave Plasma Used for Diamond Deposition

One-dimensional transport models of moderate-pressure H ₂ and H ₂ /CH ₄ plasmas obtained in a diamond deposition microwave reactor are presented. These models describe the plasma as a thermochemically nonequilibrium flow with three different energy modes. The solution of the one-dimensional plasma transport equations enabled the estimation of plasma species concentrations and temperatures on the axis of the reactor. As far as pure H ₂ plasmas are concerned, results showed that the model predictions of gas and vibration temperatures are in good agreement with experimental measurements. The model also yields a relatively good qualitative prediction of the variations of H-atom mole fraction with the power density absorbed by the plasma. The results obtained for H ₂ /CH ₄ discharges showed that the model prediction on the variations of H-atom mole fraction with methane percentage in the discharge is in good qualitative agreement with experimental results. They also showed that methane is rapidly converted to acetylene before reaching the discharge zone. The concentrations of neutral hydrocarbon species in the reactor are mainly governed by thermal chemistry. The addition of methane strongly affects the ionization kinetics of the plasma. Three major ions are generally obtained in H ₂ /CH ₄ plasmas: C ₂ H ₂ ⁺ , C ₂ H ₃ ⁺ , and C ₂ H ₅ ⁺ . The relative predominance of these ions depends on the considered plasma region and on the discharge conditions. The ionic species concentrations are also mainly governed by chemistry, except very near the substrate surface. Finally the use of this transport model along with the surface chemistry model of Goodwin ⁽¹⁾ enabled us to estimate the diamond growth rate for several discharge conditions.     

Excess enthalpies of ketone+methyl methylthiomethyl sulfoxide or +dimethyl sulfoxide at 298.15 k

Excess enthalpies of sixteen binary mixtures between one each of methyl methylthiomethyl sulfoxide (MMTSO) and dimethyl sulfoxide (DMSO) and one of ketone {CH₃CO(CH₂)_nCH₃, n=0 to 6 and CH₃COC₆H₅} have been determined at 298.15 K. All the mixtures showed positive excess enthalpies over the whole range of mole fractions. Excess enthalpies of ketone+MMTSO or DMSO increased with increasing the number of methylene radicals in the methyl alkyl ketone molecules. Excess enthalpies of MMTSO+ketone are smaller than those of DMSO+ketone for the same ketone mixtures. The limiting excess partial molar enthalpies of the ketone, H ₁ ^E,∞, in all the mixtures with MMTSO were smaller than those of DMSO. Linear relationships were obtained between limiting excess partial molar enthalpies and the number of methylene groups except 2-propanone.     

Methane conversion by an air microwave plasma

Activation of methane is carried out by means of an air microwave plasma (2.45 GHz). The experiments cover the absorbed microwave power range 350–650 W (20–50 W cm³ with 17–62%, of methane in the gas mixture, with pressures of 10–66 mbar and flow rates of 140700 ml min¹. Methane, dioxygen, and dinitrogen consumptions as well as C₂ hydrocarbons, carbon monoxide, and dihydrogen yields are analyzed hr gas chromatography. The distance of methane addition from the end of the discharge plays an important role in the composition and the concentration of the products obtained. This distance mainly determines the energy concentrated in the active species of the plasma when they react with methane. A kinetic mechanism jar the activation and decay of inethane and for the formation of C₂ hydrocarbons and carbon monoxide is discussed based on the experimental results and kinetic data in the literature.     

Deposition of Diamondlike Carbon Film and Mass Spectrometry Measurement in CH4/N2 RF Plasma

The deposition of diamondlike carbon (DLC) film and the measurements of ionic species by means of mass spectrometry were carried out in a CH₄/N₂ RF (13.56 MHz) plasma at 0.1 Torr. The film deposition rate greatly depended on both CH₄/N₂ composition ratio and RF power input. It was decreased monotonically as CH₄ content decreased in the plasma and then rapidly diminished to negligible amounts at a critical CH₄ content, which became large for higher RF power. The rate increased with increasing RF power, reaching a maximum value in 40% CH₄ plasma. The predominant ionic products in CH₄/N₂ plasma were NH⁺ ₄ and CH₄N⁺ ions, which were produced by reactions of hydrocarbon ions, such as CH⁺ ₃, CH⁺ ₂, CH⁺ ₅, and C₂H⁺ ₅ with NH₃ molecules in the plasma. It was speculated that the production of NH⁺ ₄ ion induced the decrease of C₂H⁺ ₅ ion density in the plasma, which caused a reduction in higher hydrocarbon ions densities and, accordingly, in film deposition rate. The N⁺ ₂ ion sputtering also plays a major role in a reduction of film deposition rate for relatively large RF powers. The incorporation of nitrogen atoms into the bonding network of the DLC film deposited was greatly suppressed at present gas pressure conditions.     

C2(X1Σg+)自由基与不饱和碳氢化合物反应的温度效应

运用脉冲激光光解-激光诱导荧光(PLP-LIF)的方法在293-573 K的温度范围内测量了C₂(X¹Σ_g⁺)自由基与不饱和碳氢化合物(C₂H₄和C₂H₂)气相反应的双分子反应速率常数. 获得的速率常数可以用Arrhenius 公式表达如下(单位: cm³·molecule^-1·s^-1): k(C₂H₄)=(1.16±0.10)×10^-10exp[(290.68±9.72)/T], k(C₂H₂)=(1.36±0.02)×10^-10exp[(263.85±7.60)/T], 误差为2σ. 由获得的双分子反应速率常数及其所呈现的负温度效应, 我们认为在293-573 K温度范围内C₂(X¹Σ_g⁺)自由基和不饱和碳氢化合物的反应遵循加成机理.     

Gram-Scale Synthesis of an Ultrastable Microporous Metal-Organic Framework for Efficient Adsorptive Separation of C2H2/CO2 and C2H2/CH4

A highly water and thermally stable metal-organic framework (MOF) Zn₂(Pydc)(Ata)₂ (1, H₂Pydc = 3,5-pyridinedicarboxylic acid; HAta = 3-amino-1,2,4-triazole) was synthesized on a large scale using inexpensive commercially available ligands for efficient separation of C₂H₂ from CH₄ and CO₂. Compound 1 could take up 47.2 mL/g of C₂H₂ under ambient conditions but only 33.0 mL/g of CO₂ and 19.1 mL/g of CH₄. The calculated ideal absorbed solution theory (IAST) selectivities for equimolar C₂H₂/CO₂ and C₂H₂/CH₄ were 5.1 and 21.5, respectively, comparable to those many popular MOFs. The Q_st values for C₂H₂, CO₂, and CH₄ at a near-zero loading in 1 were 43.1, 32.1, and 22.5 kJ mol⁻¹, respectively. The practical separation performance for C₂H₂/CO₂ mixtures was further confirmed by column breakthrough experiments.     

H2在K0-MWCNTs上储存和吸附/脱附特性研究

利用高压容积法辅以卸压升温脱附排水法, 测定金属K修饰多壁碳纳米管对H₂的吸附储存容量. 结果表明, 在室温(25 ℃), 7.25 MPa实验条件下, x%K⁰-MWCNTs (x%＝30%～35%, 质量百分数)对H₂的吸附储存容量可达3.80 wt%(质量百分数), 是相同条件下单纯MWCNTs氢吸附储量的2.5倍; 室温下卸至常压的脱附氢量为3.36 wt%(占总吸附氢量的～88%), 后续升温至673 K的脱附氢量为0.41 wt%(占总吸附氢量的～11%). 利用LRS和H₂-TPD-GC/MS等谱学方法对H₂/K⁰-MWCNTs吸附体系的表征研究表明, H₂在K⁰-MWCNTs上吸附存在非解离 (即分子态)和解离(即原子态)两种吸附态; 在≤723 K温度下, H₂/K⁰-MWCNTs体系的脱附产物几乎全为H₂气; 723 K以上高温脱附产物不仅含H₂, 也含有CH₄, C₂H₄和C₂H₂等C₁/C₂-烃.     

Redox-induced hydrogen transfer from hydrofullerene C60H36 to fullerene C60

The possibility of hydrogen transfer from hydrofullerene C₆₀H₃₆ to electrogenerated radical anion C₆₀ ^.− or dianion C₆₀ ²⁻ in propylene carbonate-toluence (3∶2, v/v) was demonstrated by cyclic voltammetry. The process affords C₆₀H₂ as the product. The reaction found is the typical redox-induced process. Translated fromIzvestiya Akodemii Nauk. Seriya Khimicheskaya, No. 6, pp. 1136–1139, June, 1998.     

Rate constants for the elementary reactions between CN radicals and CH4, C2H6, C2H4, C3H6, and C2H2 in the range: 295 ⩽ T/K ⩽ 700

Pulsed laser photolysis, time-resolved laser-induced fluorescence experiments have been carried out on the reactions of CN radicals with CH₄, C₂H₆, C₂H₄, C₃H₆, and C₂H₂. They have yielded rate constants for these five reactions at temperatures between 295 and 700 K. The data for the reactions with methane and ethane have been combined with other recent results and fitted to modified Arrhenius expressions, k(T) = A′(298) (T/298)ⁿ exp(?θ/T), yielding: for CH₄, A′(298) = 7.0 × 10^?13 cm³ molecule^?1 s^?1, n = 2.3, and θ = ?16 K; and for C₂H₆, A′(298) = 5.6 × 10^?12 cm³ molecule^?1 s^?1, n = 1.8, and θ = ?500 K. The rate constants for the reactions with C₂H₄, C₃H₆, and C₂H₂ all decrease monotonically with temperature and have been fitted to expressions of the form, k(T) = k(298) (T/298)ⁿ with k(298) = 2.5 × 10^?10 cm³ molecule^?1 s^?1, n = ?0.24 for CN + C₂H₄; k(298) = 3.4 × 10^?10 cm³ molecule^?1 s^?1, n = ?0.19 for CN + C₃H₆; and k(298) = 2.9 × 10^?10 cm³ molecule^?1 s^?1, n = ?0.53 for CN + C₂H₂. These reactions almost certainly proceed via addition-elimination yielding an unsaturated cyanide and an H-atom. Our kinetic results for reactions of CN are compared with those for reactions of the same hydrocarbons with other simple free radical species. © John Wiley & Sons, Inc.     

Conversion of NO in NO/N2, NO/O2/N2, NO/C2H4/N2 and NO/C2H4/O2/N2 Systems by Dielectric Barrier Discharge Plasmas

An experimental study on the conversion of NO in the NO/N₂, NO/O₂/N₂, NO/C₂H₄/N₂ and NO/C₂H₄/O₂/N₂ systems has been carried out using dielectric barrier discharge (DBD) plasmas at atmospheric pressure. In the NO/N₂ system, NO decomposition to N₂ and O₂ is the dominating reaction; NO conversion to NO₂ is less significant. O₂ produced from NO decomposition was detected by an on-line mass spectrometer. With the increase of NO initial concentration, the concentration of O₂ produced decreases at 298 K, but slightly increases at 523 K. In the NO/O₂/N₂ system, NO is mainly oxidized to NO₂, but NO conversion becomes very low at 523 K and over 1.6% of O₂. In the NO/C₂H₄/N₂ system, NO is reduced to N₂ with about the same NO conversion as that in the NO/N₂ system but without NO₂ formation. In the NO/C₂H₄/O₂/N₂ system, the oxidation of NO to NO₂ is dramatically promoted. At 523 K, with the increase of the energy density, NO conversion increases rapidly first, and then almost stabilizes at 93–91% of NO conversion with 61–55% of NO₂ selectivity in the energy density range of 317–550 J L⁻¹. It finally decreases gradually at high energy density. A negligible amount of N₂O is formed in the above four systems. Of the four systems studied, NO conversion and NO₂ selectivity of the NO/C₂H₄/O₂/N₂ system are the highest, and NO/O₂/C₂H₄/N₂ system has the lowest electrical energy consumption per NO molecule converted.     

Generation of fullerenyl radicals and chemiluminescence in the (C<Subscript>60</Subscript>—R<Subscript>3</Subscript>Al)—O<Subscript>2</Subscript> system

Fullerenyl radicals (FR) RC₆₀ ^· and chemiluminescence (CL) are generated in the presence of O₂ in C₆₀—R₃Al (R = Et, Buⁱ) solutions in toluene (T = 298 K). The FR are formed due to the addition of the R^· radical, which is an intermediate of R₃Al autooxidation, to C₆₀. Mass spectroscopy and HPLC were used to identify Et_nC₆₀H_m (n, m = 1–6), Et_pC₆₀ (p = 2–6), and dimer EtC₆₀C₆₀Et as stable products of FR transformations. As found by ESR, the EtC₆₀ ^· radical (g = 2.0037) is also generated by photolysis of solutions obtained after interaction in the (C₆₀— R₃Al)—O₂ system. In the presence of dioxygen, the FR is not oxidized but yields complexes with O₂, which appear as broadening of the ESR signals. Chemiluminescence arising in the (C₆₀—R₃Al)—O₂ system is much brighter (I _max = 1.86·10⁸ photon s⁻¹ mL⁻¹) than the known background CL (I _max = 6.0·10⁶ photon s⁻¹ mL⁻¹) for the autooxidation of R₃Al and is localized in a longer-wavelength spectral region (λ_max = 617 and 664 nm). This CL is generated as a result of energy transfer from the primary emitter ³CH₃CHO* to the products of FR transformation: R_nC₆₀H_m, R_pC₆₀, and EtC₆₀C₆₀Et. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 205–213, February, 2007.     

Synthesis,characterization and luminescence of the tetranuclear gold cluster: [Au4{7,8-(PPh2)2-7,8-C2B9H10}2(PPh3)2]

A tetranuclear gold cluster has been synthesized by the reaction of [Au(PPh₃)NO₃] with the closo carborane diphosphine 1,2-(PPh₂)₂-1,2-C₂B₁₀H₁₀ in THF, and characterized by elemental analysis, FT-IR, ¹H and ¹³C?NMR spectroscopy and X-ray structure determination. The cluster crystallizes in the triclinic Pī, a?=?15.118(8)?Å, b?=?16.057(9)?Å, c?=?24.284(13)?Å, α?=?80.822(9)°, β?=?79.624(8)°, γ?=?81.938(8)°, Z?=?2, R ₁?=?0.0626, wR ₂?=?0.1894. A single crystal structure determination showed that four gold atoms form a tetrahedral framework. Among these four gold atoms, two were chelated by two nido carborane diphosphine [7,8-(PPh₂)₂-7,8-C₂B₉H₁₀]^? anions coming from the degradation of the initial closo ligand 1,2-(PPh₂)₂-1,2-C₂B₁₀H₁₀, while the other two were ligated to two PPh₃ groups. The luminescence of this cluster was also investigated in dichloromethane solution at room temperature.     

Molecular structure of nickel(II) and copper(II) N,N′-ethylene-bis(acetylacetoneiminates) MO2N2C12H18 according to gas-phase electron diffraction data and quantum-chemical calculations

The molecular structure of nickel(II) and copper(II) N,N′-ethylene-bis(acetylacetoneiminates), NiO₂N₂C₁₂H₁₈ and CuO₂N₂C₁₂H₁₈, at 442(5) K and 425(5)K, respectively. Both molecules have C ₂ symmetry with a nearly planar MN₂O₂ coordination site and internuclear distances r _h1(M-O) = 1.862(10)/1.923(17) Å and r _h1(M-N) = 1.879(10)/1.947(18) Å for Ni(acacen) and Cu(acacen), respectively. The structure of free molecules is close to the structure of molecules in crystal. The DFT/3LYP quantum-chemical calculations (CEP-31G and 6-31G* basis sets) gave a molecular structure that agreed satisfactorily with the one found in experiment. The low-spin ¹ A and high-spin ³ A states of the Ni(acacen) molecule were considered. It was found that a change in multiplicity caused significant changes in the geometrical and electronic structure of the MN₂O₂ coordination site. As shown by experiment and calculations for the NiO₂N₂C₁₂H₁₈ molecule, the low-spin ¹ A state is the ground state. The internal rotation of CH₃(CN) and CH₃(CO) methyl groups was studied by the 3LYP/CEP-31G method. It was shown that steric hindrances led to a high rotation barrier of the CH₃(CN) group.     

Ti3C2Tx/MnO2正极在水系锌电池中的电化学性能

二氧化锰(MnO₂)材料具有比容量大、电极电位高、储量丰富以及价格低廉等优势,成为水系锌电池正极最受关注的一类材料,然而其仍然存在着结构稳定性差和电化学储存机理复杂的问题。因此,我们通过两步合成法制备了一种花苞状结构的MnO₂负载在Ti₃C₂T_x表面形成Ti₃C₂T_x/MnO₂复合材料,通过X射线粉末衍射(XRD)、X射线光电子能谱(XPS)、透射电子显微镜(TEM)和高分辨透射电子显微镜(HRTEM)对复合样品的结构、成分和形貌进行表征。通过将Ti₃C₂T_x/MnO₂复合材料作为正极,与锌负极匹配组装成水系锌电池,研究了其分别在2 mol·L^-1 ZnSO₄、2 mol·L^-1 ZnSO₄+0.1 mol·L^-1 MnSO₄、30 mol·L^-1三氟甲基磺酸四乙基铵(TEAOTf)+1 mol·L^-1三氟甲烷磺酸锌(ZnOTf)和3 mol·L^-1 ZnOTf四种电解液中的电化学性能。结果表明,Ti₃C₂T_x/MnO₂在2 mol·L^-1 ZnSO₄中的比容量较高,但循环稳定性很差。将TEAOTf盐和ZnOTf盐共溶于水中,设计了一种新型的含惰性阳离子的超高浓度盐包水电解液(30 mol·L^-1 TEAOTf+1 mol·L^-1 ZnOTf),不仅提高了Ti₃C₂T_x/MnO₂材料的可逆性,而且有效抑制了电极材料在循环过程中的溶解。     

Vibrational spectra,conformational stability,barriers to internal rotation,r0 structural parameters and ab initio calculations of fluoromethyl methyl ether

The far-infrared spectrum of gaseous fluoromethyl methyl ether, FCH₂OCH₃, along with three of the deuterium isotopes, has been recorded at a resolution of 0.10 cm^–1 in the 350 to 50 cm^–1 region. The fundamental asymmetric torsional and methyl torsional modes are extensively mixed and have been observed at 182 and 132 cm^–1, respectively, for the stablegauche conformer with the lower frequency band having several excited states falling to lower frequency. An estimate is given for the potential function governing the asymmetric rotation. On the basis of a one-dimensional model the barrier to internal rotation of the methyl moiety is determined to be 527±9 cm^–1 (1.51±0.03 kcal/mol). A complete assignment of the vibrational fundamentals for all four isotopic species observed from the infrared (3500 to 50 cm^–1) spectra of the gas and solid and from the Raman (3200 to 10 cm^–1) spectra of the gas, liquid, and solid is proposed. No evidence could be found in any of the spectra for the high-energytrans conformer. All of these data are compared to the corresponding quantities obtained from ab initio Hartree-Fock gradient calculations employing the 3-21G and 6-31G* basis sets along with the 6-31G* basis set with electron correlation at the MP2 level. Additionally, completer ₀ geometries have been determined from the previously reported microwave data and carbon-hydrogen distances determined from infrared studies. The heavy-atom structural parameters (distances in Å, angles in degrees) arer(C₁-F) = 1.395 ± 0.005;r(C₁-O) = 1.368 ± 0.007;r(C₂-O) = 1.426 ±0.003; FC₁O = 111.33 ± 0.25; C₁OC₂ = 113.50 ± 0.18 and dih FC₁OC₂ = 69.12 ± 0.26. All of these results are discussed and compared with the corresponding quantities obtained for some similar molecules.     

Kinetics of the thermal decomposition of [Co(NH3)6]2(C2O4)3·4H2O

The thermal decomposition of [Co(NH₃)₆]₂(C₂O₄)₃·4H₂O was studied under isothermal conditions in flowing air and argon. Dissociation of the above complex occurs in three stages. The kinetics of the particular stages thermal decomposition have been evaluated. The R_N and/or A_M models were selected as those best fitting the experimental TG curves. The activation energies,E, and lnA were calculated with a conventional procedure and by a new method suggested by Kogaet al. [10, 11]. Comparison of the results have showed that the Arrhenius parameters values estimated by the use of both methods are very close. The calculated activation energies were in air: 96 kJ mol^–1 (R_1.575, stage I); 101 kJ mol^–1 (Ain1.725 stage II); 185 kJ mol^–1 (A _2.9, stage III) and in argon: 66 kJ mol^–1 (A _1.25, stage I); 87 kJ mol^–1 (A _1.825, stage II); 133 kJ mol^–1 (A _2.525, stage III).     

Formation of different products during photo-catalytic reaction on TiO<Subscript>2</Subscript> suspension in water with and without 2-propanol under diverse ambient conditions

Studies on photo-catalytic reduction of CO₂ using TiO₂ photo-catalyst (0.1%, w/v) as a suspension in water was carried out at 350 nm light. CO₂ from both commercially available source, as well as generated in situ through 2-propanol oxidation, was used for this study. The photolytic products such as hydrogen (H₂), carbon monoxide (CO) andmethane (CH₄) generated were monitored in TiO₂ suspended aqueous solution with and without a hole scavenger, viz., 2-propanol. Similar photolytic experiments were also carried out with varying ambient such as air, O₂, N₂ and N₂O. The yields of CO and CH₄ in all these systems under the present experimental conditions were found to be increasing with light exposure time. H₂ yield in N₂-purged systems containing 2-propanol was found to be more as compared to the without 2-propanol system. The rate of H₂ production in N₂-purged aqueous solutions containing 0.1% TiO₂ suspension were evaluated to be 0.226 and 5.8 μl/h, without and with 0.5 M 2-propanol, respectively. This confirmed that 2-propanol was an efficient hole scavenger and it scavenged photo-generated holes (h⁺), allowing its counter ion, viz., e⁻, to react with water molecule/H⁺ to yield more H₂. The formation of both CO and CH₄ in the photolysis of CO₂-purged aqueous solutions containing suspended TiO₂ in absence of 2-propanol reveal that the generation of CH₄ is taking place mainly through CO intermediate. In presence of air/O₂, the yield of H₂ in the system without 2-propanol was observed to be negligible as compared to the system containing 2-propanol in which low yield of H₂ was obtained with a formation rate of approx. 0.5 μl/h.