可见光驱动的光催化产氢同时诱导低能核反应嬗变钾为钙（英文）

报道了曙红、氯铂酸钾、氧化石墨烯和三乙醇胺混合物悬浮体系在可见光照射条件下将钾嬗变为钙的现象.在大于440 nm光照的条件下,反应体系可以产生大量的氢气,同时体系中的部分钾原子转变为钙元子.在反应过程中,悬浮混合物中的钙元素浓度持续增加,同时伴随发生质子的还原为氢和部分质子反应为氦3和氦4的反应.分析表明,在自然界的某种环境和条件下,钙有可能通过在温和条件下的低能核反应(LENR)经历钾的嬗变生成,这个过程可能与光催化产氢过程中生成的负氢有关.     

关于在钾与负氢混合物中钾钙嬗变的检测

报道了在室温下钾与负氢混合物中钾钙发生嬗变的现象，负氢是由NaBH₄、LiBH₄和NH₃BH₃提供的.实验中的钾和钙的浓度分别用诱导耦合等离子发射光谱法（ICP-OES）和诱导耦合等离子质谱法（ICP-MS）进行检测.ICP-OES结果表明随着混合物中钾浓度的降低伴随着钙的浓度增加.此外ICP-MS结果还表明⁴⁰Ca浓度的增加伴随着⁴¹K浓度的增加，可能表明在负氢存在的条件下混合物中⁴⁰Ca的生成与⁴¹K物种有关.     

半导体CdS悬浮体系中可见光催化产氢同时生成氦-3和氦-4

我们报道了在可见光照射下,半导体硫化镉(GdS)悬浮体系在催化分解水制氢同时会伴随着少量氦-3和氦-4产生.结果表明,在温和条件下自水中的质子通过低能核反应(LENR)产生氦-3和氦-4的是可能的.     

半导体CdS悬浮体系中可见光催化产氢同时生成氦-3（英文）

我们报道了在可见光照射下,半导体硫化镉(CdS)悬浮体系在催化分解水制氢同时会伴随着少量氦-3和氦-4产生.结果表明,在温和条件下自水中的质子通过低能核反应(LENR)产生氦-3和氦-4的是可能的.     

二氧化碳: 一种同时提供亲核中心保护和亲电中心活化的试剂 XI:2-取代四氢噻唑的新合成方法

四氢噻唑和正丁基锂反应生成的N-锂代四氢噻唑(2)与二氧化碳作用生成N-羟酸锂盐3; 3然后在叔丁基锂作用下失去2-位质子形成相应的2-位碳阴离子4; 该碳阴离子和一系列亲电试剂反应, 并在酸性条件下除去保护基团得产物-2-取代四氢噻唑7. 在此过程中, 二氧化碳既是氨基的保护基团, 同时又活化了2-位亲电中心.此方法不需分离各步中间体, 产率中等.     

第二配位层磺酸根在电催化析氢反应中的作用（英文）

析氢反应涉及电子和质子转移过程,即PCET过程,需要较大的过电势才可以驱动析氢反应发生.因此,合成过电势低,活性高的催化剂成为研究热点.自然界中,铁铁氢化酶可以将质子高效地还原成氢气.经研究,铁铁氢化酶的结构中有一个氨基基团位于活性金属中心铁的一侧,因此可以精准、有效地将质子传递给金属铁,从而提高催化效率.受自然界启发,很多分子催化剂模拟了自然界中氢化酶的结构,在分子内引入proton-relay基团,促进了析氢过程中PCET的过程.但目前只有关于这类分子催化剂通过促进质子传输进而提高催化效率的文献报道,尚未发现有关其改变氢氢成键方式的研究.前期工作中,本课题组设计合成了卟啉镓并用于电催化质子还原的研究.利用循环伏安法对其析氢活性进行了测试,发现分别以三氟乙酸(TFA)和醋酸(HOAc)作为质子源时,催化析氢的电化学行为不同.在强酸(TFA)体系中,催化剂在经历了两电子还原后,生成的金属氢化物可以直接和质子发生反应,生成氢气.但是在弱酸(HOAc)体系中,生成的金属氢化物需要再经过一电子的还原才可以驱动整个催化反应的进行.在该工作的基础上,通过调研文献得知,在分子内引入酸基团时,可以极...     

二氧化碳:一种同时提供亲核中心保护和亲电中心活化的试剂 Ⅺ.2-取代四氢噻唑的新合成方法

四氢噻唑和正丁基锂反应生成的 N-锂代四氢噻唑(2)与二氧化碳作用生成 N-羟酸锂盐3;3然后在叔丁基锂作用下失去2-位质子形成相应的2-位碳阴离子4;该碳阴离子和一系列亲电试剂反应,并在酸性条件下除去保护基团得产物2-取代四氢噻唑7.在此过程中,二氧化碳既是氨基的保护基团,同时又活化了2-位亲电中心.此方法不需分离各步中间体,产率中等.     

孤岛渣油超临界水-合成气中悬浮床加氢裂化反应研究 Ⅱ. 不同氢源下的加氢裂化反应

为了研究替代氢源加氢的有效性,对孤岛渣油以磷钼酸为催化剂,在不同氢源(CO+H2/H2O、CO/H2O、H2/H2O、H2)中悬浮床加氢裂化反应进行了研究。结果表明,超临界水中现场发生的水-气转化反应提供的加氢氢源是一种具有高加氢活性的原子态氢。在适宜的反应条件下,孤岛渣油在超临界水-合成气中的加氢裂化反应过程在抑制生焦、反应产物分布等方面与对应的分子氢存在下孤岛渣油加氢裂化反应结果几乎一致,反应体系中水的存在主要作用是提供水-气转化反应的条件,在没有水-气转化发生的体系中,水的存在对加氢过程有抑制作用,总之、利用现场发生水-气转化反应为加氢提供氢源的孤岛渣油超临界水-合成气中悬浮床催化加氢裂化是一项有效的渣油加氢改质技术。     

铜催化芳香醛和酮的氢硼化转化合成苄基硼酸酯类化合物（英文）

有机硼化合物广泛应用于合成化学、药物化学以及材料化学等领域,开发新颖实用的方法合成有机硼化合物是重要的研究领域.在各种有机硼化合物中,苄基硼酸酯有着一些特有的性质,例如活性相对较高,可以有效地当作苄基化试剂使用.目前已有多种合成苄基硼酸酯的方法,主要集中在苄基格氏试剂或者锂试剂的硼化反应,但是该方法底物兼容性较差,而且苄基格氏试剂或者锂试剂的制备比较困难.随着催化反应的发展,过渡金属(如Pd,Cu,Ni,Fe)催化苄基卤代物的硼化反应及芳基卤代物和1,1-二硼类化合物的偶联反应能够有效地合成这类化合物.一级苄醇在钯或铜的催化作用下也可以转化为苄基硼酸酯.苄基C–H键的催化硼化是潜在的构建苄基硼酸酯的高原子经济性的方法,但目前其选择性和反应活性仍不高.在无金属催化的条件下,对甲苯磺酰腙类化合物与HBpin或B_(2pin_2)发生1,2-金属迁移是合成苄基硼酸酯的有效方法.到目前为止,虽然有很多种合成苄基硼酸酯的方法,但仍无法满足其合成需求,因此开发新型的方法合成苄基硼酸酯具有重要的意义.本文开发了一种新型的铜催化芳香醛/酮类化合物的脱氧氢硼化转化体系.使用廉价易得的铜作为催化剂,叔丁醇钠或者叔丁醇钾作为碱,醇质子作为氢源,在100℃的条件下,芳香醛和芳香酮可直接转化成一级和二级苄基硼酸酯类化合物,该反应操作简单,反应体系可以兼容多种官能团,分离产率在21%–77%之间.反应机理方面,该转化有两种可能的过程,(1)反应体系中首先生成1,1-偕二硼化合物,该化合物在碱和EtOH的作用下发生脱硼质子解,最终转化成苄基单硼化合物;(2)醇质子转化成负氢物种,并与体系中的冄-OBpin硼酸酯生成四配位硼,发生1,2-迁移后得到目标产物.为了验证上述两种反应途径的可行性,我们进行了一系列的控制试验.首先合成了苯乙酮的1,1-二硼化合物,在催化量碱与当量醇的作用下,以99%的收率得到了脱硼质子解的产物,说明1,1-二硼化合物可以在反应体系中转化成苄基单硼化合物.以苯甲醛作为原料合成了冄-OBpin硼酸酯,首先将其投入到甲醇、叔丁醇钠和B_(2pin_2)的体系中,最终得到了47%的苄基单硼;同时将冄-OBpin硼酸酯投入到HBpin与叔丁醇钠的体系中,得到了57%的苄基单硼化合物,说明第二种反应过程通过1,2-迁移得到目标产物也是可行的.在当前的实验条件下,两种反应路径都是可能的.     

光催化降解污染物制氢反应与原位红外表征

研究了在Pt/TiO2悬浮体系中单组分和双组分污染物为电子给体光催化分解水制氢反应. 比较了污染物甲醛、甲酸和草酸为电子给体光催化放氢反应效率，发现其活性为：草酸 >甲酸 >甲醛.原位ATR（衰减全反射）红外研究结果表明，光催化放氢活性与污染物吸附特性有关.还研究了草酸与甲酸双组分污染物体系的光解水放氢和污染物降解动力学，发现总的放氢和污染物降解速率与污染物组分在TiO2表面的吸附强度和溶液浓度有关.污染物在TiO2表面的竞争吸附决定了反应动力学.原位ATR-IR方法研究双组分混合物体系的吸附，直观地证实了上述结果.     

溴染料敏化担载Pt石墨烯催化可见光制氢、氘和氦

3He是理想的核聚变燃料,但是地球上3He的储量十分有限,大约只有500 kg.我们报道了在可见光光照条件下,溴染料敏化担载Pt石墨烯催化水还原为氢气过程中伴生少量氘和氦的实验现象.结果表明在温和条件下自水中的质子生产氘和氦的是可能的.     

Nuclear-chemical processes under the conditions of laser ablation of metals in aqueous media (problems of “cold fusion”)

A brief review of results on initiation of nuclear transformations under conditions of the laser ablation of metals in aqueous media upon exposure to picosecond laser impulses with peak intensity J _E ～ 10¹⁰–10¹³ W/cm², which is orders of magnitude less than required for the direct initiation of nuclear processes, J _E ～ 10¹⁸–10¹⁹ W/cm², is presented. It is shown that the decay rate of radioactive nuclei (using the example of uranium 238) increases significantly (by orders of magnitude), nucleus transmutation processes are initiated (using the example of the transmutation of mercury 196 nuclei into gold 197), and the nuclear fusion of light elements occurs (using the example of tritium nuclei) under such conditions. Concepts regarding the processes of inelastic (with the generation of neutrino-antineutrino pair) interactions between electrons of high (on the chemical scale) energies (～5–10 eV) and nuclei are developed in order to understand the totality of the current experimental data on the initiation of such processes under conditions of the laser ablation of metals in solutions of ordinary and heavy water. This is reflected in the definition of such processes as nuclear-chemical. It is suggested that the state of nuclear matter in nuclei formed during such interactions is in an unbalanced in-shake-up state, and cannot be pictured in the standard manner, as an ensemble of a certain number of nucleons. Such states are reactive for a wide class of nuclear transformations.     

Photocatalyzed Hydrogen Evolution from Water by a Composite Catalyst of NH2‐MIL‐125(Ti) and Surface Nickel(II) Species

A composite of the metal–organic framework (MOF) NH₂‐MIL‐125(Ti) and molecular and ionic nickel(II) species, catalyzed hydrogen evolution from water under UV light. In 95 v/v % aqueous conditions the composite produced hydrogen in quantities two orders of magnitude higher than that of the virgin framework and an order of magnitude greater than that of the molecular catalyst. In a 2 v/v % water and acetonitrile mixture, the composite demonstrated a TOF of 28 mol H₂ g(Ni)^?1 h^?1 and remained active for up to 50 h, sustaining catalysis for three times longer and yielding 20‐fold the amount of hydrogen. Appraisal of physical mixtures of the MOF and each of the nickel species under identical photocatalytic conditions suggest that similar surface localized light sensitization and proton reduction processes operate in the composite catalyst. Both nickel species contribute to catalytic conversion, although different activation behaviors are observed.     

Water Splitting via Decoupled Photocatalytic Water Oxidation and Electrochemical Proton Reduction Mediated by Electron‐Coupled‐Proton Buffer

Water splitting mediated by electron‐coupled‐proton buffer (ECPB) provides an efficient way to avoid gas mixing by separating oxygen evolution from hydrogen evolution in space and time. Though electrochemical and photoelectrochemcial water oxidation have been incorporated in such a two‐step water splitting system, alternative ways to reduce the cost and energy input for decoupling two half‐reactions are desired. Herein, we show the feasibility of photocatalytic oxygen evolution in a powder system with BiVO₄ as a photocatalyst and polyoxometalate H₃PMo₁₂O₄₀ as an electron and proton acceptor. The resulting reaction mixture was allowed to be directly used for the subsequent hydrogen evolution with the reduced H₃PMo₁₂O₄₀ as electron and proton donors. Our system exhibits excellent stability in repeated oxygen and hydrogen evolution, which brings considerable convenience to decoupled water splitting.     

Multicomponent QM study on the reaction of HOSO + NO2 with H2O: Nuclear quantum effect on structure and reaction energy profile

The hydrogen transfer reaction in the reaction of HOSO + NO₂ with and without H₂O have been investigated using multicomponent quantum-mechanics method, which can directly take nuclear quantum effect (NQE) of light nuclei into account. For the case of the reaction without H₂O, our calculation reveals that the reaction leading to trans-HONO is preferred. For the reaction with H₂O, water-non-mediated and water-mediated (hydrogen-relay) hydrogen transfer mechanism are investigated. The NQE of hydrogen nucleus lowers the relative energy of the stationary point structures and reduces the activation barrier of the reactions. The largest stabilization is found in the transition state structure of the hydrogen-relay type reaction. H/D isotope effects for the reactions are also analyzed. In particular, H/D isotope effect on the activation barrier is analyzed in detail with the aid of the active strain model.     

Organic Additive-derived Films on Cu Electrodes Promote Electrochemical CO2 Reduction to C2+ Products Under Strongly Acidic Conditions

Electrochemical CO₂ reduction (CO₂R) at low pH is desired for high CO₂ utilization; the competing hydrogen evolution reaction (HER) remains a challenge. High alkali cation concentration at a high operating current density has recently been used to promote electrochemical CO₂R at low pH. Herein we report an alternative approach to selective CO₂R (>70 % Faradaic efficiency for C₂₊ products, FE_C2+) at low pH (pH 2; H₃PO₄/KH₂PO₄) and low potassium concentration ([K⁺]=0.1 M) using organic film-modified polycrystalline copper (Modified-Cu). Such an electrode effectively mitigates HER due to attenuated proton transport. Modified-Cu still achieves high FE_C2+ (45 % with Cu foil /55 % with Cu GDE) under 1.0 M H₃PO₄ (pH≈1) at low [K⁺] (0.1 M), even at low operating current, conditions where HER can otherwise dominate.     

Vanadium determination in chloride matrices using ICP-MS: finding the optimum collision/reaction cell parameters for suppressing polyatomic interferences

Efficiencies of He/NH₃ and He/H₂ collision gases were compared in a conventional type of hexapole cell of an inductively coupled plasma mass spectrometer (ICP-MS). The optimum conditions [hexapole and quadrupole bias voltage (V_H and V_Q) and collision/reaction gas flow rates] were tested for vanadium determination (⁵¹V) in chloride matrices. When the He/H₂ mixture was used, the optimum values of V_H and V_Q were −10.0 and −8.0 V, respectively. This set-up corresponds to the kinetic energy discrimination effect. When the He/NH₃ mixture was used, the optimum values of V_H and V_Q were +10.0 and −7.0 V, respectively. Positive V_H values correspond to the ion kinetic energy effect, which allows the reactivity of the ions entering the collision/reaction cell with the reaction gas to be controlled. The obtained results showed that the He/H₂ mixture is not optimal for V determination in samples containing chlorides due to the insufficient suppression of the polyatomic interference of ³⁵Cl¹⁶O⁺. Data obtained from vanadium determination using the He/NH₃ mixture were consistent for all selected Cl⁻ concentrations, and the results were acceptable. The detection limit was comparable with detection limits obtained from ICP-MS equipped with a dynamic reaction cell. Analyses of elements forming interfering molecules, e.g., iron (⁵⁶Fe), arsenic (⁷⁵As) and selenium (⁸⁰Se), were in good agreement with the certified values for both studied collision/reaction gas mixtures.     

Highly Efficient Photocatalytic H2 Evolution from Water using Visible Light and Structure‐Controlled Graphitic Carbon Nitride

The major challenge of photocatalytic water splitting, the prototypical reaction for the direct production of hydrogen by using solar energy, is to develop low‐cost yet highly efficient and stable semiconductor photocatalysts. Herein, an effective strategy for synthesizing extremely active graphitic carbon nitride (g‐C₃N₄) from a low‐cost precursor, urea, is reported. The g‐C₃N₄ exhibits an extraordinary hydrogen‐evolution rate (ca. 20 000 μmol h^?1 g^?1 under full arc), which leads to a high turnover number (TON) of over 641 after 6 h. The reaction proceeds for more than 30 h without activity loss and results in an internal quantum yield of 26.5 % under visible light, which is nearly an order of magnitude higher than that observed for any other existing g‐C₃N₄ photocatalysts. Furthermore, it was found by experimental analysis and DFT calculations that as the degree of polymerization increases and the proton concentration decreases, the hydrogen‐evolution rate is significantly enhanced.     

Structural Transformation of SnS2 to SnS by Mo Doping Produces Electro/Photocatalyst for Hydrogen Production

SnS and SnS₂ are layered semiconductors, with potential promising properties for electro- and photocatalytic hydrogen (H₂) production. The vast knowledge in preparation and modification of layered structures was still not employed successfully in this system to fully maximize its potential. Here, the first report of structural transformation of SnS₂ into SnS with Mo-doping as a bifunctional catalyst for the hydrogen evolution reaction (HER) is reported. The structural phase transition optimized the properties of the material, providing a more delicate morphology with additional catalytic sites. The electrochemical studies showed overpotential of 377 mV at 10 mA cm⁻² for HER with Tafel slopes of 100 mV dec⁻¹ in 0.5 m H₂SO₄ for 10 % Mo-SnS. The same structure acts as an efficient photocatalyst in the generation of H₂ from water under visible illumination with rate of 0.136 mmol g⁻¹ h⁻¹ of H₂, which is 20 times higher than pristine SnS₂ under visible light.