Hierarchical boroncarbonitride nanosheets as metal-free catalysts for enhanced oxidative dehydrogenation of propane

Abstract

Boroncarbonitrides (BCNs) are recently developed new catalytic system for efficient oxidative dehydrogenation (ODH) of alkanes to alkenes. Herein, a series of novel hierarchical BCN materials are synthesized using asymmetric hydrogen bonds self-assembly between methylguanidine and boric acid, along with ammonia deposition. The XRD, S(T)EM, and XPS characterizations confirm the presence of ternary BCN solid solution covered by small serrated-like BCN nanosheets materials in the 2D plates. The unique hierarchical structure and developed mesoporosity of the BCN material contribute to its outstanding catalytic performance. The optimal catalyst delivers robust catalytic performance and long-term stability in the ODH of propane reaction with propylene and total olefin selectivity of 74.7% and 89.7% at a stable 20.4% propane conversion, much better than BCN sheets and h-BN catalyst. Results show that the in-situ formation of suitable amounts of amorphous BOX species within the BCN structure, along with the maintenance of the 2D skeleton at elevated temperatures, is a significant contribution in the enhanced ODH reactivity. Moreover, density functional theory calculation also demonstrates that the presence appropriate carbon content in BCN catalysts can significantly promote the ODH of propane reaction.