Promoting effect of nickel hydroxide on the electrocatalytic performance of Pt in alkaline solution

Abstract

Despite intense research in the past decades, the lack of high-performance catalysts for fuel cell reactions remains a challenge in realizing fuel cell applications. Herein, we report a novel hybrid nanomaterial of platinum–nickel hydroxide–nanotubes (Pt/Ni(OH)₂/CNTs) for improving electrocatalytic performance in alkaline environments. Ni(OH)₂ was directly grown on functionalized nanotubes and then, Pt nanoparticles were in situ immobilized by the microwave synthesis method. Due to electronic and synergistic effects, 10 : 2–Pt/Ni(OH)₂/N-CNT catalyst exhibited 2.77 times specific activity and 6.27 times mass activity toward methanol oxidation reaction (MOR), which were higher than those of commercial Pt/C in alkaline solution. The CO-stripping experiments and hydrogen evolution reaction (HER) further demonstrated that Ni(OH)₂ could promote oxidation removal of carbonaceous poison for MOR via accelerating water dissociation: (i) Ni(OH)₂ acted on an H₂O molecule, leading to the formation of OH_ad; (ii) OH_ad oxidized the intermediate CO_ad to CO₂. Furthermore, the 10 : 2–Pt/Ni(OH)₂/N-CNT catalyst also exhibited 2.07 times specific activity and 1.67 times mass activity toward oxygen reduction reaction (ORR), which were higher than those of commercial Pt/C in alkaline solution and Pt/N-CNT catalysts. Thus, the preparation of this hybrid nanomaterial provides a new direction for catalyst performance optimization towards next-generation fuel cells in alkaline environments.