Coupling Enteromorpha prolifera-derived N-doped biochar with Cu-Mo2C clusters for selective CO2 hydrogenation to CO
Xueyuan Pan, Caikang Wang, Bei Li, Mingzhe Ma, Hao Sun, Guowu Zhan, Kui Wang, Mengmeng Fan, Linfei Ding, Gengtao Fu, Kang Sun, Jianchun Jiang
Abstract
CO 2 conversion to CO via the reverse water-gas shift (RWGS) reaction is limited by a low CO 2 conversion rate and CO selectivity. Herein, an efficient RWGS catalyst is constructed through Enteromorpha prolifera –derived N-rich mesoporous biochar (EPBC) supported atomic-level Cu-Mo 2 C clusters (Cu-Mo 2 C/EPBC). Unlike traditional activated carbon (AC) supported Cu-Mo 2 C particles (Cu-Mo 2 C/AC), the Cu-Mo 2 C/EPBC not only presents the better graphitization degree and larger specific surface area, but also uniformly and firmly anchors atomic-level Cu-Mo 2 C clusters due to the existence of pyridine nitrogen. Furthermore, the pyridine N of Cu-Mo 2 C/EPBC strengthens an unblocked electron transfer between Mo 2 C and Cu clusters, as verified by X-ray absorption spectroscopy. As a result, the synergistic effect between pyridinic N anchoring and the clusters interaction in Cu-Mo 2 C/EPBC facilitates an improved CO selectivity of 99.95% at 500 °C compared with traditional Cu-Mo 2 C/AC (99.60%), as well as about 3-fold CO 2 conversion rate. Density functional theory calculations confirm that pyridine N-modified carbon activates the local electronic redistribution at Cu-Mo 2 C clusters, which contributes to the decreased energy barrier of the transition state of CO∗+O∗+2H∗, thereby triggering the transformation of rate-limited step during the redox pathway. This biomass-derived strategy opens perspective on producing sustainable fuels and building blocks through the RWGS reaction. N-doped biochar supported Cu-Mo 2 C cluster (Cu-Mo 2 C/EPBC) was constructed via an Enteromorpha prolifera -derived strategy. Unlike traditional Cu-Mo 2 C/AC (activated carbon), Cu-Mo 2 C/EPBC presents the better graphitization degree and larger specific surface area, while can firmly anchors Cu-Mo 2 C clusters due to riched pyridine-N. Cu-Mo 2 C/EPBC shows an improved CO selectivity of 99.95 % at 500 °C compared with Cu-Mo 2 C/AC (99.60 %), and about 3-fold CO 2 conversation rate. • Enteromorpha prolifera -derived mesoporous biochar supported Cu-Mo 2 C catalyst was prepared. • The existence of pyridine N in EPBC facilitates the formation of atomic-level Cu-Mo 2 C clusters. • Cu-Mo 2 C/EPBC exhibits the high conversation rate for selective CO 2 hydrogenation to CO.