Ultrafine PtCo Alloy Nanoclusters Confined in N-Doped Mesoporous Carbon Spheres for Efficient Ammonia Borane Hydrolysis
Lin-Xin Yin, Tingting Zhang, Kaiqing Dai, Bing Zhang, Xu Xiang, Huishan Shang
Abstract
Developing cost-effective and high-efficiency catalysts for efficient ammonia borane (AB) hydrolysis is highly desirable but remains a great challenge. Ultrafine catalysts are attractive candidates in catalysis owing to abundant surface atoms. Herein, a series of ultrafine PtxCo1–x alloy nanoclusters with an average size of 1.6 nm are homogeneously anchored within the mesoporous channels of N-doped mesoporous carbon spheres (N-MCSs) through an enhanced strong electrostatic adsorption (SEA) strategy. The ultrafine PtCo nanoclusters confined in N-MCSs lead to superior catalytic performance toward the AB hydrolysis reaction. Particularly, the optimal Pt0.33Co0.67/N-MCSs catalyst exhibits excellent performance toward the AB hydrolysis reaction. The results reveal that the highest specific rate achieves 4902 molH2 molPt–1 min–1, which is approximately 18 times higher than that of the monometallic Pt/N-MCSs catalyst. Mechanistic studies adopting kinetic isotope effects demonstrate that the O–H cleavage of H2O molecules is the rate-determine step in the AB hydrolysis reaction. Inspired by the above results, a possible reaction mechanism is proposed, which will give a new viewpoint for the rational design of cost-effective catalysts for AB hydrolysis.