Electrocatalysis can enable efficient energy storage and conversion and thus is an effective way to achieve carbon neutrality. The unique structure and function of organisms can offer many ideas for the design of electrocatalysts, which has become one of the most promising research directions. Recently, the understanding of the mechanism of bio-inspired electrocatalysis has become clearer, which has promoted the design of bio-inspired catalysts and catalytic systems. Various bio-inspired catalysts (enzyme-like catalysts, layered porous catalysts, superhydrophobic/superhydrophilic surfaces, and so on) have been developed to enable efficient electrocatalytic reactions. Herein, we discuss the key advances in the field of bio-inspired electrocatalysts progressed in recent years. First, the role of bio-inspiration in increasing the intrinsic activity and number of active sites of catalysts is introduced. Then, the structure and mechanism of layered porous catalytic systems that mimic biological transport systems are comprehensively discussed. Subsequently, the design of three-phase interfaces from micro-nanoscale to atomic scale is highlighted, including the wettability of the electrode surface and the transport system near the electrode. We conclude the review by identifying challenges in bio-inspired electrocatalysts and providing insights into future prospects for the exciting research field.

Recent advancement of proton exchange membrane fuel cells has led to commercial sales of fuel-cell cars but market barrier exists because this technology heavily relies on platinum catalyst. Given the permission of adopting platinum-group-metal-free catalysts, anion-exchange membrane fuel cell has received notable attention. However, the sluggish kinetics of anodic hydrogen oxidation reaction (HOR) largely limit the cell efficiency. Although many high-performance HOR catalysts have been reported, there are analytical uncertainties in the literature concerning the assessment of the catalyst activity. Here we determine the origin of false HOR currents in the recorded polarization curves and propose a rigorous approach to eliminate them. We unveil experimentally the uncertainties of obtaining exchange current densities (j₀) using Tafel plot from Bulter–Volmer equation and recommend employing the micro-polarization region method. For bulky catalysts that cannot establish a well-defined diffusion layer, we suggest applying external stirring bar to offer certain level of enforced convection and using j₀ to compare the activity.

Although nickel-based catalysts display good catalytic capability and excellent corrosion resistance under alkaline electrolytes for water splitting, it is still imperative to enhance their activity for real device applications. Herein, we decorated Ni_0.85Se hollow nanospheres onto reduced graphene oxide (RGO) through a hydrothermal route, then annealed this composite at different temperatures (400 °C, NiSe₂-400 and 450 °C, NiSe₂-450) under argon atmosphere, yielding a kind of NiSe₂/RGO composite catalysts. Positron annihilation spectra revealed two types of vacancies formed in this composite catalyst. We found that the NiSe₂-400 catalyst with dual Ni-Se vacancies is able to catalyze the oxygen evolution reaction (OER) efficiently, needing a mere 241 mV overpotential at 10 mA·cm^-2. In addition, this catalyst exhibits outstanding stability. Computational studies show favorable energy barrier on NiSe₂-400, enabling moderate OH^- adsorption and O₂ desorption, which leads to the enhanced energetics for OER.