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1.
Role of graphene in improving catalytic behaviors of AuNPs/MoS2/Gr/Ni-F structure in hydrogen evolution reaction
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Xian-Wu Xiu 《中国物理 B》2021,30(8):88801-088801
The efficient production of hydrogen through electrocatalytic decomposition of water has broad prospects in modern energy equipment. However, the catalytic efficiency and durability of hydrogen evolution catalyst are still very deficient, which need to be further explored. Here in this work, we prove that introducing a graphene layer (Gr) between the molybdenum disulfide and nickel foam (Ni-F) substrate can greatly improve the catalytic performance of the hybrid. Owing to the excitation of local surface plasmon resonance (LSPR) of gold nanoparticles (NPs), the electrocatalytic hydrogen releasing activity of the MoS2/Gr/Ni-F heterostructure is greatly improved. This results in a significant increase in the current density of AuNPs/MoS2/Gr/Ni-F composite material under light irradiation and in the dark at 0.2 V (versus reversible hydrogen electrode (RHE)), which is much better than in MoS2/Gr/Ni-F composite materials. The enhancement of hydrogen release can be attributed to the injection of hot electrons into MoS2/Gr/Ni-F by AuNPs, which will improve the electron density of MoS2/Gr/Ni-F, promote the reduction of H2O, and further reduce the activation energy of the electrocatalyst hydrogen evolution reaction (HER). We also prove that the introduction of graphene can improve its stability in acidic catalytic environments. This work provides a new way of designing efficient water splitting system. 相似文献
2.
《Physics letters. A》2020,384(12):126368
Electrochemical water splitting to generate hydrogen could be an important part of future renewable energy, but faces challenge due to the scarcity of effective earth-abundant electrocatalysts and insufficient understanding of catalytic mechanism. Herein, we predicated strain-induced changes in electronic structure and catalytic performance of low-cost two-dimensional Fe3S4 material. The calculations disclose that the half-metallic feature evolves into metallicity under applied external strain, which makes Gibbs adsorption free energy of hydrogen close to zero. Different from traditional doping and defecting strategies, this work demonstrates that excellent catalytic activity for water splitting can be achieved by inducing a small lattice deformation in Fe3S4 monolayer. Our findings provide new inspirations for the steering of electronic structure and designing of new-type catalysts. 相似文献
3.
The development of cost-effective and active water-splitting electrocatalysts is an essential step toward the realization of sustainable energy. Its success requires an intensive improvement in the kinetics of the anodic half-reaction of the oxygen evolution reaction (OER), which determines the overall system efficiency to a large extent. In this work, we designed a facile and one-route strategy to activate the surface of metallic nickel (Ni) for the OER in alkaline media by ultrasound (24 kHz, 44 W, 60% acoustic amplitude, ultrasonic horn). Sonoactivated Ni showed enhanced OER activity with a much lower potential at + 10 mA cm−2 of + 1.594 V vs. RHE after 30 min ultrasonic treatment compared to + 1.617 V vs. RHE before ultrasonication. In addition, lower charge transfer resistance of 11.1 Ω was observed for sonoactivated Ni as compared to 98.5 Ω for non-sonoactivated Ni. In our conditions, ultrasound did not greatly affect the electrochemical surface area (Aecsa) and Tafel slopes however, the enhancement of OER activity can be due to the formation of free OH• radicals resulting from cavitation bubbles collapsing at the electrode/electrolyte interface. 相似文献
4.
The poor efficiency and stability of cost-effective metal compounds are major hurdles to substitute expensive metal-based nanomaterials for the hydrogen evolution reaction (HER). As a result, new concepts and tactics for developing electrocatalysts based on earth-abundant elements must be developed. We present iron-nickel alloy nanoparticles that are supported with carbon (FeNi@C) to improve HER performance in alkaline conditions. FeNi particle was supported on Trimesic acid (TMA) based carbon. In particular, the high conductivity of the carbon and a large number of catalytically active sites in the FeNi demonstrated a synergistic effect, making the hybrid structure a good choice for HER catalyst. Moreover, the physicochemical interaction between the carbon and FeNi metal enhanced the electrocatalytic performance and resulted in achieving 10 mA/cm2 current density at 190 mV overpotential with 15 h chronopotential cycling, proving the possibility for replacing costly Pt-based catalysts. 相似文献
5.
Contamination of water resources by pharmaceutical residues, especially during the time of pandemics, has become a serious problem worldwide and concerns have been raised about the efficient elimination of these compounds from aquatic environments. This study has focused on the development and evaluation of the sonocatalytic activity of a flower-like MoS2/CNTs nanocomposite for the targeted degradation of hydroxychloroquine (HCQ). This nanocomposite was prepared using a facile hydrothermal route and characterized with various analytical methods, including X-ray diffraction and electron microscopy, which results confirmed the successful synthesis of the nanocomposite. Moreover, the results of the Brunauer–Emmett–Teller and diffuse reflectance spectroscopy analyses showed an increase in the specific surface area and a decrease in the band gap energy of the nanocomposite when compared with those of MoS2. Nanocomposites with different component mass ratios were then synthesized, and MoS2/CNTs (10:1) was identified to have the best sonocatalytic activity. The results indicated that 70% of HCQ with the initial concentration of 20 mg/L could be degraded using 0.1 g/L of MoS2/CNTs (10:1) nanocomposite within 120 min of sonocatalysis at the pH of 8.7 (natural pH of the HCQ solution). The dominant reactive species in the sonocatalytic degradation process were identified using various scavengers and the intermediates generated during the process were detected using GC–MS analysis, enabling the development of a likely degradation scheme. In addition, the results of consecutive sonocatalytic cycles confirmed the stability and reusability of this nanocomposite for sonocatalytic applications. Thus, our data introduce MoS2/CNTs nanocomposite as a proficient sonocatalyst for the treatment of pharmaceutical contaminants. 相似文献
6.
Nickel and its alloys have recently been emerged as potential catalytic electrode materials for hydrogen evolution reaction in alkaline media. The present work contemplates reinforcement of electroless Ni-P plate with ZrO2. The plate showed very high stability and excellent electrocatalytic activity. In situ incorporation of ZrO2 resulted in increase in the rate of deposition of Ni on steel substrate. There was high activation during the initial stage of the plating also. The electrocatalytic activity of the ZrO2-reinforced Ni electroless plate was found to be highly reproducible and long lasting when used for hydrogen evolution reaction. 相似文献
7.
基于密度泛函理论的第一性原理方法,本文计算了单层2H相MoSe2纳米材料表面及两种边缘(Mo原子边缘、Se原子边缘)不同活性位点、不同氢原子吸附率下的氢吸附吉布斯自由能(Gibbs free energy,用△GH0表示),并且将对应的微观结构进行了系统分析比较,得出△GH0最接近于0 eV的吸附位点及相应的吸附率.同时,结合差分电荷密度和电负性理论,分析了单层MoSe2两种边缘氢吸附的电荷转移及成键特性,进一步解释了不同吸附位点呈现的结构与能量趋势.最后,通过基于密度泛函理论的第一性原理分子动力学模拟,研究了高温热运动对两种边缘氢吸附的影响,获得了氢原子发生脱附的临界温度及对应的微观动态过程.该理论研究从原子尺度揭示了单层2H相MoSe2纳米材料边缘不同位点在不同温度下对氢原子吸附和脱附的微观机理,证实了Mo原子边缘的畸变和重构行为,加深了对实验中单层2H相MoSe2边缘在不同温度下氢吸附机理的理解,为实验中通过控制MoSe2边缘设计廉价高效的析氢催化剂提供理论参考. 相似文献
8.
A visible-light boron and nitrogen co-doped titania (B-N-TiO2) photocatalyst was prepared by sol-gel method with titanium tetra-n-butyl oxide, urea and boric acid as precursors. The photocatalyst was characterized by Fourier Transform Infrared (FT-IR), UV-vis diffusive reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), BET and electrochemistry method. Photocatalytic activity for hydrogen production over platinized B-N-TiO2 under visible-light (λ ≥ 420 nm) irradiation was investigated. In nitrogen doped titania (N-TiO2) NTiO bond is formed, which extends the absorption edge to the visible-light region. A part of doping boron enters into titania lattice and most of the boron exists at the surface of the catalyst. The crystallite size of B-N-TiO2 decreases compared to N-TiO2, while its photocurrent and the surface hydroxyl group increase. Furthermore, doping boron could act as shallow traps for photoinduced electrons to prolong the life of the electrons and holes. Therefore, the visible-light activity of B-N-iO2 increases greatly compared with that of N-TiO2. 相似文献
9.
A general scheme for the screening of heterogeneous catalysts using density functional theory (DFT) calculations is presented, and the scheme is illustrated with a search for catalysts for the hydrogen evolution reaction. Simple techniques to estimate the activity of binary surface and bulk alloys for this reaction are described, and several computational tests for stability in reaction environments are presented. Careful application of these activities and stability criteria to a database of DFT calculations on ∼750 binary transition metal alloys leads to the identification of several surface and bulk alloys that are predicted to perform comparably to platinum, the canonical hydrogen evolution catalyst. This study marks the first use of full DFT calculations for high-throughput screening of transition metal catalysts. 相似文献
10.
本文采用化学还原法制备了系列Ni纳米团簇(NCs)修饰的板钛矿TiO2准纳米立方块(Ni/BTN). 结果表明,Ni NCs的负载量和氧化态对Ni/BTN复合材料的光吸收、光催化活性和稳定性均存在显著的影响. 在制备的系列Ni NCs负载产物中,0.1%Ni/BTN复合材料的光催化产氢活性(156 μmol/h)最佳,为单纯的BTN产氢活性(36 μmol/h)的4.3倍. 进一步的研究结果表明,Ni NCs的超细尺寸(∽2 nm)和高分散性有利于快速捕获BTN的光生电子,从而可缩短光生电荷的传输距离和提高BTN 的光催化活性. 结果证明了板钛矿TiO2是一类潜在的高效光催化材料,为采用低成本Ni基助催化剂进一步提高其光催化性能的研究提供了重要的思路. 相似文献
11.
Rapid technological development requires sustainable, pure, and clean energy systems, such as hydrogen energy. It is difficult to fabricate efficient, highly active, and inexpensive electrocatalysts for the overall water splitting reaction: the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). The present research work deals with a simple hydrothermal synthesis route assisted with ultrasound that was used to fabricate a 3D nanoflower-like porous CoMoS4 electrocatalyst. A symmetric electrolyzer cell was fabricated using a CoMoS4 electrode as both the anode and cathode, with a cell voltage of 1.51 V, to obtain a current density of 10 mA/cm2. Low overpotentials were observed for the CoMoS4 electrode (250 mV for OER and 141 mV for HER) at a current density of 10 mA/cm2. 相似文献
12.
Co-doped flower-like SnS2 was synthesized using a one-step hydrothermal method. The Co content of Co-doped SnS2 was facilely tuned by controlling the [Co]/[Sn] molar concentration ratio (SC-x; x = 0.05, 0.5, 1.0 2.0, where x indicates the [Co]/[Sn] ratio). The morphology of the samples did not significantly change despite changes in the Co dopant content. Compared to SC-0 (667 mV), SC-0.05 (400 mV), SC-0.5 (382 mV), and SC-1.0 (374 mV), SC-2.0 showed higher catalytic performance, with an overpotential of 323 mV at a current density of 10 mA/cm2 in 1 M KOH solution. Moreover, SC-2.0 exhibited high stability for 12 h during chronopotentiometry. SC-2.0 was unexpectedly transformed to weakly crystallized CoOOH nanoparticles after the stability test. The transformation rate from Co-doped SnS2 to CoOOH was decreased with an increase in the Co content. 相似文献
13.
Laser fragmentation in liquid synthesis of novel palladium-sulfur compound nanoparticles as efficient electrocatalysts for hydrogen evolution reaction
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Guo-Shuai Fu 《中国物理 B》2022,31(7):77901-077901
One promising way to tune the physicochemical properties of materials and optimize their performance in various potential applications is to engineer material structures at the atomic level. As is well known, the performance of Pd-based catalysts has long been constrained by surface contamination and their single structure. Here, we employed an unadulterated top-down synthesis method, known as laser fragmentation in liquid (LFL), to modify pristine PdPS crystals and obtained a kind of metastable palladium-sulfur compound nanoparticles (LFL-PdS NPs) as a highly efficient electrocatalyst for hydrogen evolution reaction (HER). Laser fragmentation of the layered PdPS crystal led to a structural reorganization at the atomic level and resulted in the formation of uniform metastable LFL-PdS NPs. Noteworthy, the LFL-PdS NPs show excellent electrocatalytic HER performance and stability in acidic media, with an overpotential of -66 mV at 10 mA· cm-2, the Tafel slope of 42 mV· dec-1. The combined catalytic performances of our LFL-PdS NPs are comparable to the Pt/C catalyst for HER. This work provides a top-down synthesis strategy as a promising approach to design highly active metastable metal composite electrocatalysts for sustainable energy applications. 相似文献
14.
For the alkaline fuel cell cathode reaction, it is very essential to develop novel catalysts with superior catalytic properties. Here, we report the synthesis of highly active and stable MoS2/Pd composites for the oxygen reduction reaction (ORR), via a simple, eco-friendly sonochemical method. The bulk MoS2 was first transformed into single and few layers MoS2 nanosheets through ultrasonic exfoliation. Then the exfoliated MoS2 nanosheets served as supporting materials for the nucleation and further in-situ growth of Pd nanoparticles to form MoS2/Pd composites via ultrasonic irradiation. Cyclic voltammetry and rotating disk voltammetry measurements demonstrate that as-prepared MoS2/Pd composites which provides a direct four-electron pathway for the ORR, have better electrocatalytic activity, long-term operation stability than commercial Pt/C catalyst. We expect that the present work would provide a promising strategy for the development of efficient oxygen reduction electrocatalyst. In addition, this study can also be extended to the preparation of other hybrid with desirable morphologies and functions. 相似文献
15.
We have established a model for the water forming reaction on Pd in the temperature range 350–475 K. Importantly, the model takes into account the possibility that hydrogen may absorb and adsorb at interface sites on supported Pd catalysts. It is shown that already at modest conditions interface adsorption may significantly affect reaction rates. The model may also be used to quantify the response of a hydrogen sensitive Pd-MOS device during hydrogen sensing in oxygen. In the case of Pd supported on SiO2, the concentration of interface sites is so low that interface hydrogen adsorption will have only a minor influence on a catalytic reaction. The fact that a Pd-MOS device may be used as a very sensitive hydrogen detector at atmospheric oxygen conditions, despite a steric oxygen blocking of hydrogen dissociation sites, is predicted by the model. 相似文献
16.
In situ growth of different numbers of gold nanoparticles on MoS_2 with enhanced electrocatalytic activity for hydrogen evolution reaction
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Producing hydrogen through a hydrogen evolution reaction(HER) by splitting water at the suitable overpotential is a great alternative to solving the problems of environmental pollution and the energy crisis. Molybdenum sulfide(MoS_2)has attracted extensive attention as one of the most promising catalytic materials for HER. In this work, we design a facile method to in situ grow gold nanoparticles(Au NPs) on MoS_2. Different numbers of Au NPs with MoS_2 are used to find the best catalytic activity. Due to the larger active surface area and higher conductivity of the Au–MoS_2 composites, all the Au–MoS_2 composites exhibit more enhanced HER electroactivity than pure MoS_2. In brief, the new material architecture exhibits optimized HER activity with a low onset overpotential of 0.12 V, low Tafel slope of 0.163 V·dec~(-1), and an excellent stability in acidic solution. 相似文献
17.
Metal substrates-induced phase transformation of monolayer transition metal dichalcogenides for hydrogen evolution catalysis
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Monolayer transition metal dichalcogenides can normally exist in several structural polymorphs with distinct electrical, optical, and catalytic properties. Effective control of the relative stability and transformation of different phases in these materials is thus of critical importance for applications. Using density functional theory calculations, we investigate the effects of low-work-function metal substrates including Ti, Zr, and Hf on the structural, electronic, and catalytic properties of monolayer MoS2 and WS2. The results indicate that such substrates not only convert the energetically stable structure from the 1H phase to the 1T'/1T phase, but also significantly reduce the kinetic barriers of the phase transformation. Furthermore, our calculations also indicate that the 1T' phase of MoS2 with Zr or Hf substrate is a potential catalyst for the hydrogen evolution reaction. 相似文献
18.
The adsorption and surface reactions of CH2I2 on the K-dosed Mo2C/Mo(1 0 0) have been studied by high resolution electron energy loss spectroscopy, X-ray photoelectron spectroscopy and thermal desorption spectroscopy. Potassium is an effective promoter for the rupture of C-I bond in the adsorbed CH2I2. A partial dissociation of this compound occurred even at 100 K and was completed at 190 K at monolayer K coverage. The dissociation was further promoted by the illumination of coadsorbed layer at 100 K. As revealed by HREELS and XPS measurements the primary products of the dissociation are CH2 and I. Methylene was converted to π-bonded ethylene characterized by Tp = 160 K, and di-σ-ethylene with Tp = 350 K. Other products of the surface reaction are hydrogen and methane. The coupling reaction of CH2 species was clearly facilitated by potassium. The effect of potassium was explained by the extended electron donation to adsorbed alkyl iodide in one hand, and by the direct interaction between potassium and I on the other hand. 相似文献
19.
Qingquan Kong Xuguang An Lin Huang Xiaolian Wang Wei Feng Siyao Qiu Qingyuan Wang Chenghua Sun 《Frontiers of Physics》2021,16(5):53506
Heterojunction structure has been extensively employed for the design of novel catalysts. In the present study, density functional theory was utilized to investigate the electronic structure and hydrogen evolution performance of Ti3C2O2 MXene quantum dots/graphene (QDs/G) heterostructure. Results show that a slight distortion can be observed in graphene after hybriding with QDs, due to which the electronic structure of QDs have been changed. Associated with such QDs-graphene interaction, the catalytic activity of Ti3C2O2 QDs has been optimized, leading to excellent HER catalytic performance. 相似文献
20.
The present article reports the synthesis of hybrid structure along with non-precious cobalt-disulfide. A simple hydrothermal method was used to fabricate multi-faceted CoS2 introduced graphene aerogels. Studies on electrocatalytic activity showed that the presence of CoS2 facets along with graphene aerogel played a prominent role in the enhancement of proton reduction to hydrogen gas. The CoS2/graphene aerogel hybrid sample exhibits extremely low overpotential (160 mV vs. RHE), and high current density for HER in acidic solution. The activity enhancement can be attributed to increasing the active electrochemical surface area of graphene aerogel and faceted particles inside the 3D matrix of graphene. Furthermore, the CoS2/graphene hybrid retained its high activity even after 1000 cycles of cyclic voltammetry scans, signifying longer stability under acidic condition. The results suggest that CoS2/graphene aerogel hybrids show their potential application to hydrogen evolution reaction. 相似文献