Mesoporous single crystals have unique potentials in catalysis, but remain unexplored owing to their grand synthetic challenge. Herein, we report a facile soft-template method to prepare palladium and palladium alloy nanocubes with single-crystallinity and abundant mesoporosity. The successful formation of these exotic nanostructures essentially relies on the co-introduction of cetyltrimethylammonium chloride as the surfactant template and extra Clions as the facet-selective capping agent under well controlled experimental conditions. Thanks to their large surface areas and penetrating mesoporous channels, our products exhibit great performances for electrochemical CO 2 reduction. The best sample from alloying palladium with copper enables the efficient formate production with high selectivity (90~100%) over a broad potential range, and great stability even under the working potential as cathodic as -0.5 V versus reversible hydrogen electrode. These performance metrics are far superior to previous Pd-based materials, and underscore the structural advantages of our products.

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The electrosynthesis of recyclable ammonia (NH3) from nitrate under ambient conditions is of great importance but still full of challenges for practical application. Herein, an efficient catalyst design strategy is developed that can engineer the surface microenvironment of a PdCu hollow (PdCu‐H) catalyst to confine the intermediates and thus promote selective NH3 electrosynthesis from nitrate. The hollow nanoparticles are synthesized by in situ reduction and nucleation of PdCu nanocrystals along a self‐assembled micelle of a well‐designed surfactant. The PdCu‐H catalyst shows a structure‐dependent selectivity toward the NH3 product during the nitrate reduction reaction (NO3−RR) electrocatalysis, enabling a high NH3 Faradaic efficiency of 87.3% and a remarkable NH3 yield rate of 0.551 mmol h−1 mg−1 at ‐0.30 V (vs reversible hydrogen electrode). Moreover, this PdCu‐H catalyst delivers high electrochemical performance in the rechargeable zinc‐NO3− battery. These results provide a promising design strategy to tune catalytic selectivity for efficient electrosynthesis of renewable NH3 and feedstocks.

Atomically ordered Rh2P nanocluster encapsulated within a high-surface-area hollow mesoporous carbon nanoreactor is catalytically active for hydrogen production via electrocatalytic hydrogen evolution reaction and room-temperature dehydrogenation of ammonia borane.