Xin Kang

Abstract Direct seawater electrolysis is promising for sustainable hydrogen gas (H 2 ) production. However, the chloride ions in seawater lead to side reactions and corrosion, which result in a low efficiency and poor stability of the electrocatalyst and hinder the use of seawater electrolysis technology. Here we report a corrosion-resistant RuMoNi electrocatalyst, in which the in situ-formed molybdate ions on its surface repel chloride ions. The electrocatalyst works stably for over 3000 h at a high current density of 500 mA cm −2 in alkaline seawater electrolytes. Using the RuMoNi catalyst in an anion exchange membrane electrolyzer, we report an energy conversion efficiency of 77.9% and a current density of 1000 mA cm −2 at 1.72 V. The calculated price per gallon of gasoline equivalent (GGE) of the H 2 produced is $ 0.85, which is lower than the 2026 technical target of $ 2.0/GGE set by the United Stated Department of Energy, thus, suggesting practicability of the technology.

Abstract Constructing stable electrodes which function over long timescales at large current density is essential for the industrial realization and implementation of water electrolysis. However, rapid gas bubble detachment at large current density usually results in peeling-off of electrocatalysts and performance degradation, especially for long term operations. Here we construct a mechanically-stable, all-metal, and highly active CuMo 6 S 8 /Cu electrode by in-situ reaction between MoS 2 and Cu. The Chevrel phase electrode exhibits strong binding at the electrocatalyst-support interface with weak adhesion at electrocatalyst-bubble interface, in addition to fast hydrogen evolution and charge transfer kinetics. These features facilitate the achievement of large current density of 2500 mA cm −2 at a small overpotential of 334 mV which operate stably at 2500 mA cm −2 for over 100 h. In-situ total internal reflection imaging at micrometer level and mechanical tests disclose the relationships of two interfacial forces and performance of electrocatalysts. This dual interfacial engineering strategy can be extended to construct stable and high-performance electrodes for other gas-involving reactions.

Abstract Production of green hydrogen (H 2 ) by water electrolysis is important for achieving the global mission of carbon neutrality. For this, acidic water electrolysis with a higher current density operation and energy conversion efficiency compared with alkaline water electrolysis has attracted much attention. The four‐electron‐transfer oxygen evolution reaction (OER) limits the overall efficiency of water electrolysis devices. In recent years, low‐dimensional OER catalysts have been extensively explored to increase the overall efficiency of such devices, but most of them work well only at low current density and show unsatisfied long‐term stability. In this review, recent progress in acidic OER is discussed and three aspects including intrinsic activity, high current density operation, and long‐term stability are focused upon. Strategies to improve these aspects including surface chemistry engineering, constructing porous structure, and protecting the active sites’ are comprehensively reviewed. Finally, prospects for developing high‐performance catalysts with high current density operation and long‐term stability for industrial applications are proposed.

A chromium–iridium oxide electrocatalyst with an interfacial coupling effect, endowing it with high activity and stability for the oxygen evolution reaction, as well as high performance of hydrogen production in a PEM electrolyzer.

Main group indium materials have been known as promising electrocatalysts for two-electron-involved carbon dioxide reduction to produce formate, which is a key energy vector in many industrial reactions. However, the synthesis of two-dimensional (2D) monometallic nonlayered indium remains a great challenge. Here, we present a facile electrochemical reduction strategy to transform 2D indium coordination polymer into elemental indium nanosheets. In a customized flow cell, the reconstructed metallic indium exhibits a high Faradaic efficiency (FE) of 96.3% for formate with a maximum partial current density exceeding 360 mA cm–2 and negligible degradation after 140 h operation in 1 M KOH solution, outperforming the state-of-the-art indium-based electrocatalysts. Moreover, in and ex situ electrochemical analysis and characterizations demonstrate that the enhanced exposure of active sites and mass/charge transport at the CO2 gas–catalyst–electrolyte triple-phase interface and the restrained electrolyte flooding are contributing to producing and stabilizing carbon dioxide radical anion intermediates, thus leading to superior catalytic performance.