A dandelion-like amorphous composite catalyst with outstanding performance for sodium borohydride hydrogen generation. (11th March 2021) - Chen, Wenzheng
Abstract: Sodium borohydride has attracted much attention because of its high hydrogen density, low hydrolysis temperature and safety. However, most of the current catalysts are expensive and their performances are easily attenuated. Therefore, the development of new catalysts with excellent performances and low cost is the key to its application. In this work, a novel dandelion-like CoMoNi–B/ZIF-67 catalyst with excellent performance was prepared by chemical reduction at room temperature, wherein the CoMoNi–B amorphous alloy was evenly wrapped on the ZIF-67 carrier through liquid phase reduction to form a dandelion-like composite catalyst, of which the "flower bud" ZIF-67 carrier is about 500 nm, and the "crown" flocculent amorphous alloy is about 400 nm. The as-synthesized CoMoNi–B/ZIF-67 has a dandelion-like structure, uniform distribution, large specific surface area, and exhibits an excellent catalytic activity with an apparent activation energy of 35.01 kJ/mol calculated by the Arrhenius equation. Its catalytic hydrolysis rate for sodium borohydride reaches up to 6277 (mL H2 min/g Co and Ni) at 25 °C. Compared with traditional precious metal catalysts, this novel dandelion-like CoMoNi–B/ZIF-67 catalyst has simple preparation, low cost, and easy availability of raw materials, has great potential application for hydrogen generation in NaBH4 hydrolysis. Highlights: Combining ZIF-67 and CoMoNi–B alloy with high amorphization into a new catalyst. CoMoNi–B/ZIF-67 catalyst has a "dandelion-like" structure. CoMoNi–B/ZIF-67 catalyst has macroporous structure after cyclic reaction. The catalytic rate can reach 6277 (mL H2 min/g Co and Ni) at 25 °C.