Designing and constructing bifunctional electrocatalysts is vital for water splitting. Particularly, the rational interface engineering can effectively modify the active sites and promote the electronic transfer, leading to the improved splitting efficiency. Herein, free-standing and defect-rich heterogeneous MoS2/NiS2 nanosheets for overall water splitting are designed. The abundant heterogeneous interfaces in MoS2/NiS2 can not only provide rich electroactive sites but also facilitate the electron transfer, which further cooperate synergistically toward electrocatalytic reactions. Consequently, the optimal MoS2/NiS2 nanosheets show the enhanced electrocatalytic performances as bifunctional electrocatalysts for overall water splitting. This study may open up a new route for rationally constructing heterogeneous interfaces to maximize their electrochemical performances, which may help to accelerate the development of nonprecious electrocatalysts for overall water splitting.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/advs.201900246

Defect-Rich Heterogeneous MoS2/NiS2 Nanosheets Electrocatalysts for Efficient Overall Water Splitting.

Single‐Atom Ru Doping Induced Phase Transition of MoS2 and S Vacancy for Hydrogen Evolution Reaction

The hydrogen evolution reaction (HER) is an emerging key technology to provide clean, renewable energy. Current state-of-the-art catalysts still rely on expensive and rare noble metals, however, the relatively cheap and abundant transition metal dichalcogenides (TMDs) have emerged as exceptionally promising alternatives. Early studies in developing TMD-based catalysts laid the groundwork in understanding the fundamental catalytically active sites of different TMD phases, enabling a toolbox of physical, chemical, and electronic engineering strategies to improve the HER catalytic activity of TMDs. This report focuses on recent progress in improving the catalytic properties of TMDs toward highly efficient production of H2. Combining theoretical and experimental considerations, a summary of the progress to date is provided and a pathway forward for viable hydrogen evolution from TMD driven catalysis is concluded.

Engineered 2D Transition Metal Dichalcogenides—A Vision of Viable Hydrogen Evolution Reaction Catalysis

In order to relieve current energy crisis and the related environment pollutions arising with fossil fuel, the development and application of sustainable and clean energy, such as solar and hydrogen, is anticipated as a prospective issue. It is urgent and significant to develop and construct various energy storage and conversion technologies and materials for the generation and utilization of clean energy sources. Polyoxometalates (POMs), a class of metal oxide polyanion clusters, can serve as outstanding candidates in energy-related fields like electrocatalysis, rechargeable battery, photocatalysis, and proton conduction, based on their plentiful redox property, semiconductor-like feature and acidity. Here, the selected recent and significant advances in the development of POM-based materials for sustainable and clean energy conversion and storage are reviewed and summarized, and special emphases are shown to the applications of POMs as platforms for hydrogen production, water oxidation, carbon dioxide reduction, Li-ion rechargeable batteries, supercapacitors, proton-exchange membrane fuel cells, dye-sensitized solar cells and so on. The results obtained from different catalytic/energy storage systems have been compared and we try to give a better understanding on catalytic reactivity-catalysts structure correlation as well as to put a picture for the rational design of electrochemical electrodes.

Polyoxometalate-based materials for sustainable and clean energy conversion and storage

In electrocatalysis, doping regulation has been considered as an effective method to modulate the active sites of catalysts, providing a powerful means for creating a large variety of highly efficient catalysts for various reactions. Of particular interest, there has been growing research concerning the doping of two-dimensional transition-metal compounds (TMCs) to optimize their electrocatalytic performance. Despite the previous achievements, mechanistic insights of doping regulation in TMCs for electrocatalysis are still lacking. Herein, we provide a systematic overview of doping regulation in TMCs in terms of background, preparation, impacts on physicochemical properties, and typical applications including the hydrogen evolution reaction, oxygen evolution reaction, oxygen reduction reaction, CO2 reduction reaction, and N2 reduction reaction. Notably, we bridge the understanding between the doping regulation of catalysts and their catalytic activities via focusing on the physicochemical properties of catalysts from the aspects of vacancy concentrations, phase transformation, surface wettability, electrical conductivity, electronic band structure, local charge distribution, tunable adsorption strength, and multiple adsorption configurations. We also discuss the existing challenges and future perspectives in this promising field.

Doping regulation in transition metal compounds for electrocatalysis

Engineering catalytic sites at the atomic level provides an opportunity to understand the catalyst’s active sites, which is vital to the development of improved catalysts. Here we show a reliable and tunable polyoxometalate template-based synthetic strategy to atomically engineer metal doping sites onto metallic 1T-MoS2, using Anderson-type polyoxometalates as precursors. Benefiting from engineering nickel and oxygen atoms, the optimized electrocatalyst shows great enhancement in the hydrogen evolution reaction with a positive onset potential of ~ 0 V and a low overpotential of −46 mV in alkaline electrolyte, comparable to platinum-based catalysts. First-principles calculations reveal co-doping nickel and oxygen into 1T-MoS2 assists the process of water dissociation and hydrogen generation from their intermediate states. This research will expand on the ability to improve the activities of various catalysts by precisely engineering atomic activation sites to achieve significant electronic modulations and improve atomic utilization efficiencies. While heterogeneous catalysts can act as tangible, efficient materials for energy conversion, understanding the active catalytic sites is challenging. Here, authors engineer specific catalytic sites into molybdenum sulfide to improve and elucidate hydrogen evolution electrocatalysis.

/pdf/atomically-engineering-activation-sites-onto-metallic-1t-mos-2qchqw3k4m.pdf

Atomically engineering activation sites onto metallic 1T-MoS 2 catalysts for enhanced electrochemical hydrogen evolution.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

/pdf/publisher-correction-atomically-engineering-activation-sites-5fki7jol18.pdf

Ning Pu

Papers

Atomically engineering activation sites onto metallic 1T-MoS 2 catalysts for enhanced electrochemical hydrogen evolution.

Publisher Correction: Atomically engineering activation sites onto metallic 1T-MoS2 catalysts for enhanced electrochemical hydrogen evolution.