Controllable hydrogen release from NH3BH3 hydrolysis over Ru ultrafine particles stabilized on agriculture waste-derived carbon

Abstract

Simultaneously considering cost, safety and catalytic efficiency, the development of a cost-effective and high-performance catalyst is significant and challenging for controllable hydrogen release from ammonia borane (AB, NH3BH3) hydrolysis. In this work, Ru ultrafine particles are evenly and firmly stabilized on wheat straw-derived porous carbon through a facile procedure. Specifically, attributed to the abundant co-doping of heteroatoms (namely, N and O) and suitable hierarchical porous structure of WSC-1.0 with large specific surface area (1000 m2 g−1), which is prepared with a mass ratio of 1: 1 for K2CO3 to the pre-carbonized biomass waste, as well as high dispersion (32.6%) of Ru ultrafine particles with an average size of 1.4 ± 0.3 nm, the optimal Ru/WSC-1.0 displays exceptional catalytic performance in the hydrolysis of AB. The corresponding turnover frequency (TOF) and specific reaction rate (rB) are 167.7 min−1 and 4.07 × 104 mL min−1 gRu−1, respectively, and the apparent activation energy is 40.94 kJ mol−1. Upon adding NaOH (1.0 M), the hydrolysis rate can be remarkably accelerated (TOF = 401.4 min−1, rB = 9.75 × 104 mL min−1 gRu−1). The isotope experiments show that the scission of an O-H bond in H2O by oxidative addition is the decisive step in this reaction. Impressively, the effective “on-off” control for the hydrolytic dehydrogenation reaction over Ru/WSC-1.0 can be easily realized by introducing certain amounts of Zn(NO3)2 and EDTA-2Na, separately. Our work delivers a facile approach for efficient utilization of agricultural wastes and offers a robust and cost-effective catalyst for the controllable hydrogen evolution from AB hydrolysis.