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Exploring highly active and inexpensive bifunctional electrocatalysts for water‐splitting is considered to be one of the prerequisites for developing hydrogen energy technology. Here, an efficient simultaneous etching‐doping sedimentation equilibrium (EDSE) strategy is proposed to design and prepare hollow Rh‐doped CoFe‐layered double hydroxides for overall water splitting. The elaborate electrocatalyst with optimized composition and typical hollow structure accelerates the electrochemical reactions, which can achieve a current density of 10 mA cm−2 at an overpotential of 28 mV (600 mA cm−2 at 188 mV) for hydrogen evolution reaction (HER) and 100 mA cm−2 at 245 mV for oxygen evolution reaction (OER). The cell voltage for overall water splitting of the electrolyzer assembled by this electrocatalyst is only 1.46 V, a value far lower than that of commercial electrolyzer constructed by Pt/C and RuO2 and most reported bifunctional electrocatalysts. Furthermore, the existence of Fe vacancies introduced by Rh doping and the typical hollow structure are demonstrated to optimize the entire HER and OER processes. EDSE associates doping with template‐directed hollow structures and paves a new avenue for developing bifunctional electrocatalysts for overall water splitting. It is also believed to be practical in other catalysis fields as well.

Screening and developing highly efficient electrodes is key to large-scale water electrolysis. The practical industrial electrode should fulfill several criteria of high activity, structural stability, and fast bubble evolution at a large current density. In this study, a novel monolithic 3D hollow foam electrode that can achieve the requirements of large current density water electrolysis is developed and fabricated through a simple electroless plating-calcination strategy. This strong 3D Ni-Mo-B hollow foam electrode can withstand a pressure of 2.37 MPa and exhibits high electrochemical surface area, high conductivity, and low gas transfer resistance, drastically boosting its catalytic performance. It affords 50 mA cm -2 at overpotentials of only 68 mV for hydrogen evolution reaction and 293 mV for oxygen evolution reaction and can survive at a large current density of 5 A cm -2 while maintaining its structure and performance in 1.0 m KOH. The advantages of facile preparation, high mechanical strength, high gas mass transfer ability, and excellent performance enable this structure to be a potential electrode, active substrate, or 3D catalyst in many fields.

Perovskite solar cells (PSCs) have attracted more and more attention in the scientific community due to their high performance and simple fabrication process.In the past few years, emerging technologies have made manufacturing large-scale PSC modules possible. However, stability and fabrication issues still limit the modularization and commercialization of PSCs. Carbon materials have been widely used in PSCs to overcome these challenges due to their excellent optical, electrical, and mechanical properties. In addition, the hydrophobic properties of certain carbon materials are highly effective at protecting the perovskite film from moisture and improving the stability of PSCs. All these superior properties have made carbon one of the most promising materials to fabricate future highperformance PSC modules with long service lifetimes. In this review, recent developments of carbon-based materials in different layers of single-junction PSCs will first be discussed, with an emphasis on functionalities related to PSCs' stability and modularization. Then, current improvements and future discussions in the manufacturing of monolithic PSC modules will be reviewed in detail.