The removal of tar and the production of methane-rich gas from biomass hydrogen pyrolysis by using biochar-based catalysts.

[Display omitted] • Ni-Co/PWA was prepared, the tar yield was only 1.2 wt%, and the CH 4 carbon yield was 56.0 %. • DFT calculations show that the Co-Ni species reduce the adsorption energy of naphthalene. • The particle size was a main factor affecting the catalyst activity. • The reduction of C support would cause the deactivation of the catalyst. The metal-doped pine wood activated char (PWA) was used in the catalytic reforming of the pyrolysis vapor of pine sawdust in the H 2 atmosphere, to promote the removal of tar and methane-rich gas production. Ni-Co/PWA showed the best catalytic performance compared with Ni/PWA, Co/PWA, Fe/PWA, and Ni-Fe/PWA. The acquired tar yield was as low as 1.2 wt%, and the carbon yield of methane was 56.0 %. The characterization data of catalysts revealed that the NiCo active species in the catalyst was better dispersed and had a smaller particle size of 11.8 nm. Density functional theory (DFT) calculations showed that the introduction of Co reduced the adsorption energy of naphthalene on Ni/PWA catalysts. In addition, a synergistic effect of the H 2 atmosphere and the metal-doped PWA catalyst was observed by comparing the reaction products under H 2 and N 2 atmospheres. According to DFT calculations, H radical combines with naphthalene to release 104 kJ/mol of energy, promoting the decomposition of naphthalene. As a result, a high efficiency of Ni-Co/PWA in tar removal and methane generation was obtained. This study provides references for the efficient utilization of biomass energy. [ABSTRACT FROM AUTHOR]