Single Cr atom supported on boron nitride nanotubes for the reaction of N2O reduction by CO: A density functional theory study.

Single Cr atom supported on defective boron nitride nanotubes was designed as a single atom catalyst (SAC) for N 2 O reduction reaction by CO. The stepwise mechanism of N 2 O + CO reaction and catalytic performance of the SAC were studied. • Single atom catalyst on BNNT was theoretically designed for N 2 O reduction by CO. • Single Cr atom exhibits excellent activity, and is less susceptible to poisoning. • The reaction is more likely to follow the stepwise mechanism. • BNNT and Cr atom play as the electron reservoir and bridge in reaction respectively. The removal of harmful N 2 O and CO in one step has attracted extensive research interest. Here, we studied the feasibility of N 2 O + CO reaction on single atom catalysts (SACs) supported on defective boron nitride nanotube (BNNT) by means of density functional theory (DFT) calculations. The Cr single atom catalyst which can avoid catalyst poisoning was screened from five low-price transition metal atoms (Ti, Cr, Mn, Fe, and Co) based on the adsorption strength of reactant and product on catalyst. The stepwise mechanism was considered which reveals the reaction path involves N 2 O decomposition, CO oxidation and CO 2 desorption. The rate-limiting step is CO 2 desorption with the desorption barrier of 0.42 eV. Along the reaction path, optimized structures and electronic property analyses indicate Cr atom acts as bridge to transfer electron due to its 3d orbital, which plays an important role in activation of N 2 O and CO molecules. Meanwhile, BNNT support with high redox stability acts as electron reservoir, withdrawing or donating electron, to facilitate the whole reaction. Therefore, Cr/BNNT is proposed to be a promising and highly efficient catalyst for eliminating environmentally unfriendly N 2 O and CO gases simultaneously. [ABSTRACT FROM AUTHOR]