Modified CNTs interfacial anchoring and particle-controlled synthesis of amorphous cobalt-nickel-boron alloy bifunctional materials for NaBH4 hydrolysis and supercapacitor energy storage

Abstract

The advantage of composites comes from the synergy between different material, that is, the engineering of interface effects between them. Well-developed surface effects between the materials help to maximize the properties and improve the stability of the composite. Herein, CoNiB@ca-CNTs composites were successfully prepared through a simple wet chemical reduction method by reducing the metal ions pre-anchored on the surface of carboxylated modified CNTs. Co0.25Ni0.75B@ca-CNTs composite were used as electrode materials for supercapacitor. It provides high specific capacitance (2078 F g−1 under 1 A g−1), outstanding rate performance (1802 F g−1 under 10 A g−1), and good cycling stability (87.8% retention rate at 5000 cycles). The constructed Co0.25Ni0.75B@ca-CNTs//AC (activated carbon) asymmetric supercapacitor obtained 180.3 F g−1 under 1 A g−1. It has an energy density of 67.4 Wh kg−1 at 400.4 W kg−1 and good stability (84.1% retention at 5000 cycles). In addition, Co0.75Ni0.25B@CNTs was used as catalyst with excellent catalytic activity for the hydrolysis of NaBH4, with hydrogen production rates of 6245.75 mL min−1 gcatalyst−1 and 18135.16 mL min−1 gCo,Ni−1 at 25 °C and low activation of 28.67 kJ mol−1. It has good catalytic stability remaining 72.6% after 10 catalytic hydrolysis cycles. The results demonstrate that CoNiB@ca-CNTs exhibit excellent performance and stability in the field of supercapacitors and hydrogen production from NaBH4 hydrolysis. This work has a good inspiration for the development of bifunctional composite materials in the future.