Two-dimensional vermiculite carried CuCoCe catalysts for CO-SCR in the presence of O2 and H2O: Experimental and DFT calculation

Abstract

Abstract Two-dimensional (2D) materials have attracted tremendous attention as denitration catalysts for the selective catalytic reduction (SCR) reaction. Here, we prepare two-dimensional (2D) vermiculite (VMT)-supported copper–cobalt–cerium catalyst (CuCoCe/2D-VMT) by the impregnation method and employed it for the CO-SCR reaction. The NO conversion utilizing CuCoCe/2D-VMT achieves 100% at 300°C with a GHSV of 102,000\xa0h−1in the presence of 1\xa0vol% O2 and 5\xa0vol% H2O. CuCoCe/2D-VMT promotes the dispersion of the active metal-site species and boosts the reduction temperature, reduces the particle size gradually. Additionally, the in situ DRIFTS spectrum reflects the existence of Cu+−CO, νas (CO32−), νs (NO3−), (NO)2, νas (–OH), νas (COO–), and δ (HCO3−) intermediates on the CuCoCe/2D-VMT surface, it supports the following mechanism study. Further, in the DFT calculation, the transition state search and potential energy analysis, CuCoCe/2D-VMT possesses lower activation energy and higher energy gain compared with CuCo/2D-VMT in each potential reaction pathway. Largely, combined with in-situ DRIFTS and the transition-state analysis, the elementary reactions of CuCoCe/2D-VMT in the SCR pathways are proposed under the following harsh conditions: CO\xa0+\xa0NO\xa0+\xa0O2\xa0+\xa0H2O. The elementary reactions mainly includes the generation of Ov, the NO\xa0+\xa0NO process, the reaction pathways of CO reacts with *O, *OH, *H (H2O) and Ov is refilled by gaseous O2. We expect this strategy to promote the development and utilization of CO-SCR catalysts and reveal a new inexpensive and highly efficient method for practical applications.