Boosting the Electrocatalytic Performance of CoPt Alloy with Enhanced Electron Transfer via Atomically Dispersed Cobalt Sites

Ruthenium-Based Electrocatalysts for Hydrogen Evolution Reaction: from Nanoparticles to Single Atoms

Benefiting from similar hydrogen bonding energy to Pt and much lower price compare with Pt, Ru based catalysts are promising candidates for electrocatalytic hydrogen evolution reaction (HER). The catalytic activity of Ru nanoparticles can be enhanced through improving their dispersion by using different supports, and the strong metal supports interaction can further regulate their catalytic performance. In addition, single-atom catalysts (SACs) with almost 100% atomic utilization attract great attention and the coordinative atmosphere of single atoms can be adjusted by supports. Moreover, the syngenetic effects of nanoparticles and single atoms can further improve the catalytic performance of Ru based catalysts. In this review, the progress of Ru based HER electrocatalysts are summarized according to their existing forms, including nanoparticles (NPs), single atoms (SAs) and the combination of both NPs and SAs. The common supports such as carbon materials, metal oxides, metal phosphides and metal sulfides are classified to clarify the metal supports interaction and coordinative atmosphere of Ru active centers. Especially, the possible catalytic mechanisms and the reasons for the improved catalytic performance are discussed from both experimental results and theoretical calculations. Finally, some challenges and opportunities are prospected to facilitate the development of Ru based catalysts for HER.

Ultrafine PtCo alloy nanoparticles integrated into porous N-doped nanosheets for durable oxygen reduction reaction

Here, we propose a sub-3 nm small-size PtCo alloy catalyst integrated into a porous nitrogen-doped nanosheet through a space-confined and interfacial induction strategy. The designed PtCo-CoNC-P catalyst exhibits exceptional durability, with only a minimal 2 mV decline in half-wave potential after 30 000 cycles of accelerated durability tests.

Ultralow-content Pt nanodots/Ni3Fe nanoparticles: interlayer nanoconfinement synthesis and overall water splitting

Minimizing precious metal loading into electrocatalysts for water splitting is vital to promoting hydrogen energy technology toward practical applications. Low-content loading of precious-metal electrocatalysts is achieved by decorating precious metal nanostructures on co-electrocatalysts typically via surface confinement. Here, an electrocatalyst of ultralow-content Pt nanodots (0.71 wt%)/Ni3Fe nanoparticles on reduced oxidation graphene (Pt/Ni3Fe/rGO) is constructed for overall water splitting by pyrolyzing a single-source precursor PtCl63- guest-intercalated MgNiFe-layered double hydroxide (MgNiFe-LDH) host via a distinctive interlayer confinement. Consequently, Pt/Ni3Fe/rGO demonstrates attractive overpotentials of 240 and 76 mV at 10 mA cm-2 for the oxygen and hydrogen evolution reactions (OER and HER), respectively, outperforming those of its /Ni3Fe/rGO counterpart. Moreover, the Pt/Ni3Fe/rGO∥Pt/Ni3Fe/rGO electrolyzer generates a current density of 10 mA cm-2 at 1.55 V, with a retention of 92.4% after 50 h. Furthermore, the measured specific activity and low transfer resistance, as well as the density functional theory (DFT) calculations, indicate that the active Pt/Ni3Fe in Pt/Ni3Fe/rGO can optimize the adsorption/desorption of reaction intermediates and thus boost OER/HER kinetics, all of which lead to enhanced performance. The results demonstrate that such an interlayer confinement-based synthesis strategy can allow for the design of cost-effective precious nanodots as potential electrocatalysts.

Hollow CoVOx/Ag nanoprism with tailored electronic structure for high efficiency oxygen evolution reaction

Developing high-active and inexpensive electrocatalysts for oxygen evolution reaction (OER) is very important in the field of water splitting. The catalytic performance of electrocatalysts can be significantly improved by optimizing the electronic structure and designing suitable nanostructure. In this work, we represent the synthesis of hollow CoVOx/Ag-5 for OER. Due to the interaction of CoVOx and Ag nanoparticles, the electronic structure is optimized to improve the intrinsic catalytic activity. Additionally, the extrinsic catalytic activity of CoVOx/Ag is enhanced by the abundant active sites from the hollow structure. As a result, the CoVOx/Ag-5 demonstrates significantly enhanced OER catalytic activity with a low overpotential of 247 mV at 10 mA cm-2. In addition, it also exhibits excellent durability, without obvious attenuation in performance after continuous operation for 60 h. Furthermore, the catalyst can enable full water splitting with appropriate 100 % Faraday efficiency, demonstrating its practical application.

Ru doping induced interface engineering in flower-liked CoMoO4-RuO2 boosts oxygen electrocatalysis for rechargeable Zn-air battery

Constructing heterogeneous catalysts can significantly boost the electrocatalytic activity due to the improved intrinsic catalytic activity induced by tailored electronic structure and optimized chemisorption to the reaction intermediates. RuO2 based electrocatalysts are especially attractive due to the high catalytic activity of RuO2. To reduce the usage of noble metal and improve the catalytic activity of catalyst, CoMoO4-RuO2 micro-flower was synthesized using a facile hydrothermal-calcination method in this work. CoMoO4-RuO2 exhibits a low overpotential of 177 mV at 10 mA cm-2 for oxygen evolution reaction (OER) and a high half-wave potential of 0.858 V for oxygen reduction reaction (ORR). Moreover, the Zn-air battery assembled using CoMoO4-RuO2 exhibit shows a high maximum discharge power density of 149 mW cm-2 and a large open circuit voltage of 1.38 V. The good performance can be attributed to the incorporation of RuO2, which not only induces extra catalytic active sites, but also forms heterojunction with CoMoO4 to optimize the electronic structure of CoMoO4-RuO2, thereby achieving a better equilibrium of absorption and desorption of intermediates. The work provides insights into designing RuO2 based electrocatalysts for advanced electrocatalysis.