Construction of an extraordinary stable mesoporous carbocatalyst in acetylene hydrochlorination via boric acid assistance

Abstract

In recent years, metal-free carbon catalysts have garnered significant attention as substitutes for metal catalysts due to their cost-effectiveness and increased resistance to poisoning. However, the stability of metal-free carbon catalysts still lags behind that of metal catalysts, presenting a significant hurdle to industrialization. To enhance the catalytic stability of these catalysts, a boron-nitrogen co-doped mesoporous carbon (B, N-MC) catalyst was synthesized using polyacrylonitrile (PAN) as the carbon and nitrogen source, with boric acid serving as the electron regulator. The acetylene conversion on the B, N-MC(0.5) catalyst reached 62.8 % at 220 °C and gas hourly space velocity (GHSV) of C2H2 at 300 h−1, even high than 0.25%Au/AC catalyst (53.3 %). Importantly, the B, N-MC(0.5) catalyst exhibited excellent stability, maintaining its initial activity even after 500 h of evaluation. Experimental and theoretical analyses demonstrate that the B–N pairs, facilitated by the electronic regulation ability of boric acid, effectively inhibits the polymerization of acetylene molecules, mitigates the formation of carbon deposits, thereby enhancing the stability of the catalyst.