Shuo Geng

Bio: Shuo Geng is an academic researcher from Harbin Institute of Technology. The author has contributed to research in topics: Overpotential & Electrocatalyst. The author has an hindex of 11, co-authored 16 publications receiving 341 citations. Previous affiliations of Shuo Geng include Jilin Normal University.

Photocatalytic dehydrogenation of formic acid promoted by a superior PdAg@g-C3N4 Mott–Schottky heterojunction

Abstract: Herein, we report the production of a superior Mott–Schottky heterojunction that is based on PdAg nanowires (NWs) that grow in situ on graphitic carbon nitride (g-C3N4). Due to the strong Mott–Schottky effect between PdAg NWs and g-C3N4, the heterojunction enhances the photocatalytic dehydrogenation of formic acid (FA) (TOF = 420 h−1) without additives and under visible light (λ > 400 nm) at 25 °C, which is the best value among all heterogeneous catalysts reported for the photocatalytic dehydrogenation of FA. The H2 production rate is almost constant under the current reaction conditions. Detailed studies reveal that a favorable charge transfer from g-C3N4 and Ag to Pd makes Pd electron-rich, which enhances the catalytic activity and stability of the heterojunction for the photocatalytic dehydrogenation of FA under visible light. Our studies open up a new route to the design of a metal–semiconductor heterojunction for visible light-driven photocatalytic dehydrogenation of FA.

Activating interfacial S sites of MoS2 boosts hydrogen evolution electrocatalysis

Abstract: The hydrogen evolution reaction (HER) of molybdenum disulfide (MoS2) is limited in alkaline and acid solution because the active sites are on the finite edge with extended basal plane remaining inert. Herein, we activated the interfacial S sites by coupling with Ru nanoparticles on the inert basal plane of MoS2 nanosheets. The density functional theory (DFT) calculation and experimental results show that the interfacial S electronic structure was modulated. And the results of ΔGH* demonstrate that the adsorption of H on the MoS2 was also optimized. With the advantage of interfacial S sites activation, the Ru-MoS2 needs only overpotential of 110 and 98 mV to achieve 10 mA·cm−2 in both 0.5 M H2SO4 and 1 M KOH solution, respectively. This strategy paves a new way for activating the basal plane of other transition metal sulfide electrocatalysts for improving the HER performance.

Hole-rich CoP nanosheets with an optimized d-band center for enhancing pH-universal hydrogen evolution electrocatalysis

Abstract: Tailoring the d-band center is an effective method to promote the hydrogen evolution reaction (HER) activity of electrocatalysts. Herein, we demonstrate that the d-band center can be tuned through a hole-creating method to enhance pH-universal HER activity using CoP as a basic platform. The density functional theory (DFT) calculation reveals that the d-band center and the valence electron number of Co sites around the holes are upshifted, which boosts H adsorption. In addition, introducing holes into the nanosheets of CoP can optimize the ΔGH* of the Co atoms around the holes. Inspired by the DFT results, a soft template method was developed to synthesize hole-rich CoP nanosheets. With the advantages of hole-rich and unique nanosheet features, the hole-rich CoP nanosheets show low HER overpotentials with only 84 and 94 mV to achieve a current density of 10 mA cm−2 in both acidic and alkaline media, better than that of the other dimensional counterparts. In addition, the hole-rich CoP nanosheets also show satisfactory stability after long-term HER tests. This strategy of regulating the d-band center is expected to be extended to other transition metal phosphide electrocatalysts for enhancing the HER performance.

Metal oxide-based materials as an emerging family of hydrogen evolution electrocatalysts

Abstract: Hydrogen production from electrochemical water splitting represents a highly promising technology for sustainable energy storage, but its widespread implementation heavily relies on the development of high-performance and cost-effective hydrogen evolution reaction (HER) electrocatalysts. Metal oxides, an important family of functional materials with diverse compositions and structures, were traditionally believed inactive towards HER. Encouragingly, the continuous breakthroughs and significant progress in recent years (mainly from 2015 onwards) make engineered metal oxides emerge as promising candidates for HER electrocatalysis. In this article, we present a comprehensive review of recent advances in metal oxide-based electrocatalysts for HER. We start with a brief description of some key fundamental concepts of HER, such as mechanisms, computational activity descriptors, and experimental parameters used to evaluate catalytic performance. This is followed by a overview of various types of metal oxide-based HER electrocatalysts reported so far, including single transition metal oxides, spinel oxides, perovskite oxides, metal (oxy)hydroxides, specially-structured metal oxides and oxide-containing hybrids, with special emphasis on designed strategies for promoting performance and property–activity correlation. Finally, some concluding remarks and perspectives about future opportunities of this exciting field are provided.

(Invited) Contributions of Phase, Sulfur Vacancies, and Edges to the Hydrogen Evolution Reaction Catalytic Activity of Porous Molybdenum Disulfide Nanosheets

Abstract: Molybdenum disulfide (MoS2) is a promising nonprecious catalyst for the hydrogen evolution reaction (HER) that has been extensively studied due to its excellent performance, but the lack of understanding of the factors that impact its catalytic activity hinders further design and enhancement of MoS2-based electrocatalysts. Here, by using novel porous (holey) metallic 1T phase MoS2 nanosheets synthesized by a liquid-ammonia-assisted lithiation route, we systematically investigated the contributions of crystal structure (phase), edges, and sulfur vacancies (S-vacancies) to the catalytic activity toward HER from five representative MoS2 nanosheet samples, including 2H and 1T phase, porous 2H and 1T phase, and sulfur-compensated porous 2H phase. Superior HER catalytic activity was achieved in the porous 1T phase MoS2 nanosheets that have even more edges and S-vacancies than conventional 1T phase MoS2. A comparative study revealed that the phase serves as the key role in determining the HER performance, as 1T phase MoS2 always outperforms the corresponding 2H phase MoS2 samples, and that both edges and S-vacancies also contribute significantly to the catalytic activity in porous MoS2 samples. Then, using combined defect characterization techniques of electron spin resonance spectroscopy and positron annihilation lifetime spectroscopy to quantify the S-vacancies, the contributions of each factor were individually elucidated. This study presents new insights and opens up new avenues for designing electrocatalysts based on MoS2 or other layered materials with enhanced HER performance.

Non-carbon-supported single-atom site catalysts for electrocatalysis

Abstract: Single-atom site catalysts (SACs) have received considerable attention for electrocatalytic applications, owing to their maximum atom-utilization efficiency, well-identified active centers, and tunable supports. Carbon-supported SACs have been widely applied in electrocatalysis, and their progress has been intensively reviewed. Non-carbon-supported SACs have drawn ever-increasing attention recently, and are emerging as an indispensable class of SACs. This review comprehensively summarizes the recent exciting progress on the non-carbon-supported SACs and their applications in electrocatalytic reactions. Eight types of non-carbon-supported SACs are firstly categorized to show their diversity. Subsequently, the anchoring and stabilization mechanisms for each type of non-carbon-supported SACs are systematically unraveled. Furthermore, the advanced characterization techniques for identifying and monitoring the atomic structure of SACs are highlighted. Thereafter, the advances of non-carbon-supported SACs for electrochemical energy conversion are discussed, which emphasizes their applications in the hydrogen evolution reaction, the oxygen evolution reaction, the oxygen reduction reaction, the N2 reduction reaction, and the CO2 reduction reaction. Finally, perspective insights into the current challenges and the future prospects for non-carbon-supported SACs are provided.