Structure-regulated Ru particles decorated P-vacancy-rich CoP as a highly active and durable catalyst for NaBH4 hydrolysis

Abstract

NaBH4 is considered the best hydrogen storage material due to its high hydrogen content of 10.6 wt% and good stability. However, NaBH4 hydrolysis requires an efficient catalyst because of the sluggish reaction kinetics. In this work, we have demonstrated a process of preparing a cobalt phosphide-supported Ru particulate nanocatalyst with abundant phosphorus vacancies for the first time. Electron paramagnetic resonance and transmission electron microscopy revealed that the synthesized Ru9.8/r-CoP catalyst has ample phosphorus vacancies, and Ru species are small particles (~2.5 nm) with uniform dispersion, respectively. More importantly, the optimized Ru9.8/r-CoP catalyst has the lowest activation energy (45.3 kJ mol−1) and exhibits excellent catalytic performance for NaBH4 hydrolysis with a high hydrogen generation rate 9783.3 mLH2 min−1 gcat−1 at 25 °C, which is higher than most of the cobalt-based catalysts. Moreover, the Ru9.8/r-CoP catalyst also shows good reusability. For example, the catalytic performance only declined by ca. 14% after five cycles. The excellent catalytic performance of Ru9.8/r-CoP is attributed to the abundant phosphorus vacancies along with a large specific surface area of r-CoP, which makes the Ru particles smaller and more uniformly dispersed on the surface, thereby exposing more active sites to show improved performance.