MOF‐Templated Hierarchical Porous Hollow Core‐Shell Framework Cobalt Oxide for Enhancing Hydrogen Generation from Borohydride‐Based Hydrolysis

Abstract

Designing and fabricating a competent cobalt‐based catalyst for sodium borohydride (NaBH4) hydrolysis is of great importance. The present work reports the synthesis of hierarchical porous hollow core‐shell framework cobalt oxide (HCSCO) via etching and calcination processes, which is then employed for catalyzing NaBH4 hydrolysis. Various characterization analyses have been employed to reveal the surficial morphology, the hollow core‐shell framework, the crystalline structure, the fruiful formation of Co3O4, the porosity, and the chemical states of HCSCO. The as‐prepared HCSCO showed prominent catalytic hydrolysis of NaBH4 to generate H2 with a H2 generation rate of 441 ml min‐1 gcatalyst‐1 and a low activation energy (Ea) of 34.8 kJ mol‐1. This Ea value of HCSCO is substantially lower than that of other catalysts, including noble metal catalysts or composites reported in the literature. Besides, HCSCO could remain its superb activity (~100% H2 generation efficiency) over multiple hydrolysis cycles without significant changes of morphology and microstructure. The catalytic hydrolysis mechanism for H2 generation from NaBH4 using HCSCO is also proposed. This work provides a valuable strategy for the synthesis and fabrication of state‐of‐art catalysts for H2 generation from the hydrolysis of NaBH4.