Promoting Methane Dry Reforming over Ni Catalysts via Modulating Surface Electronic Structures of BN Supports by Doping Carbon

Abstract

Methane dry reforming (MDR) attracts great attention due to the comprehensive conversion and utilization of CO2 and CH4 into an equimolar ratio of H2/CO. Boron nitride-supported Ni-based catalysts show great promise for the efficient coking resistance but exhibit weak interactions with active sites and poor gas adsorption capacity. Herein, carbon-doped boron nitride (BCN) was originally developed to anchor Ni nanoparticles on the boundary or near the boundary between layers with strong interactions, which exhibited excellent MDR activity and high coking resistance. It has been demonstrated that the modification of the electronic structure of BN surfaces by doping carbon strengthens the interactions between Ni and BCN as well as the CO2 activation capacity. The stable I D/I G ratio observed during the MDR process implies that carbon doping effectively inhibits the formation of graphitic carbon by weakening the occurrence of side reaction and makes the catalysts possess excellent coking resistance. Abundant active intermediates, such as −OH groups and formate species as well as CO, were observed over Ni/BCN catalysts signifying the strong activation of CO2 and CH4 cleavage capacity, which can facilitate the MDR process. This discovery presents in-depth insights into the relationship of surface electronic structure and gas activation over Ni/BCN catalysts and also paves the way for the development of highly efficient coking- and sintering-resistant Ni-based catalysts.

Synergy of Oxygen Vacancies and Ni0 Species to Promote the Stability of a Ni/ZrO2 Catalyst for Dry Reforming of Methane at Low Temperatures

“…Besides, the surface oxygen species derived from the activation of CO 2 would react with carbon from the decomposition of methane, further forming CO, which could enhance the stability of the catalyst . Apart from the oxygen species derived from the decomposition of CO 2 , other oxidation-reducing reactions occurring on catalysts can also provide active adsorbed oxygen species (O*). , Deng et al reported that the O* species derived from the reducible oxides would contribute to the gasification of carbon deposition to form CO or CO 2 . Zhang et al also found that the restraining Ni oxidation and the dynamic variation between MoO x and MoO x C y contributed to the activity and coking resistance.…”

Emergent Ni catalysts induced by nitride-to-oxide transformation for coking and sintering resistant dry reforming of methane

“…[15][16][17] Generally, carbon deposition originates from CH 4 decomposition and CO disproportionation. 18,19 Worse will, the sintering of Ni NPs would result in more serious carbon deposition due to well graphitic carbon formation on the large Ni particles. [20][21][22] In order to solve the issues of sintering and carbon deposition, researchers proposed many solutions to improve the activity and stability of the catalysts, such as alloying with other metals, [23][24][25][26] enhancing the strong metal-support interaction (SMSI), [27][28][29] or optimizing supports to expose more active sites.…”

Ni/Co in and on CeO2: a comparative study on the dry reforming reaction

“…Noble metals such as Pt, Rh, Ru, Ir, and others have shown excellent catalytic activity for DRM. 11,21,[30][31][32][33][34] Over the years, efforts have been made to replace the expensive and rare noble metal-based catalysts with naturally abundant non-noble metals like Ni, Co, Cu, Zn, etc., based catalysts, [35][36][37] which have shown promising results towards catalyzing the DRM reaction. Ni especially has exhibited great potential for catalyzing the process, but its activity signicantly reduces due to coke deposition at high temperature.…”