Air-engaged fabrication of nitrogen-doped carbon skeleton as an excellent platform for ultrafine well-dispersed RuNi alloy nanoparticles toward efficient hydrolysis of ammonia borane

Abstract

Functional carbons that can provide abundant anchoring sites for metal nanoparticles (NPs) have shown great promise in boosting the catalytic activity for hydrolysis of ammonia borane (AB), while the synthetic recipes for some of them are complicated, time-consuming and hazardous together with a low yield. Herein, we develop a facile and easily scalable one-pot synthetic strategy to nitrogen-doped carbon skeleton (NCS) via direct pyrolysis of ethylenediamine tetra-acetic acid tetra-sodium salt in air. Attributing to the anchoring sites from abundant nitrogen-dopant and nanoporous structure of NCS, ultrasmall RuNi alloy NPs are highly distributed on NCS. The as-prepared RuNi/NCS can be used as a highly active catalyst for hydrogen production from AB hydrolysis at room temperature. Specifically, the optimal Ru1Ni1.90/NCS delivers an excellent catalytic activity with a very high turnover frequency of 1017 min−1 in basic solution, superior to many previous results. The kinetic studies indicate that AB hydrolysis catalyzed by Ru1Ni1.90/NCS is first-order and zero-order in terms of Ru and AB concentrations, respectively. Additionally, the isotopic analysis reveals that the O–H bond cleavage of water is the rate-determining step. The high catalytic activity of Ru1Ni1.90/NCS can be assigned to the ultrasmall RuNi nanostructure, highly nanoporous carbon matrix, and abundant N-dopant and the synergistic catalysis between the two metals. This study offers a simple synthetic protocol for construction of metal-carbon hybrid toward hydrogen generation from the hydrolysis of chemical storage materials.