Promoting effect of calcium substitution of La-Fe based perovskites for enhanced cellulose and lignin biomass CO2 gasification

Abstract

Biomass CO₂ gasification produces green high-quality syngas through the re-utilization of CO₂, which is a highly promising and efficient low-carbon technology. This work investigated the effect of Ca doping on CO₂ catalytic gasification performance over La-Fe based perovskite catalysts of cellulose-rich biomass (Straw, ST) and lignin-rich biomass (Coconut shell, CS) feedstocks. Comprehensive characterization techniques including XRD, XPS, SEM, BET, Raman spectra and TG were employed to analyze structural evolution and physicochemical properties. The experimental results showed that Ca doping significantly improved catalytic activity. Among them, L6C4FO exhibited superior catalytic performance compared to other samples, with total syngas yields of 1.81 times (699.62 mL/g) and 3.66 times (938.03 mL/g) higher than the non-catalytic samples of ST and CS, respectively. Moreover, it also demonstrated good stability in the cyclic gasification experiments. The characterization results revealed two compensation mechanisms dependent on Ca doping levels. Below 40 % substitution at A-sites, oxygen vacancy formation served as the primary charge compensation mechanism, substantially enhancing gasification activity. At higher doping concentrations (>40 %), the increase in Fe valence state became main compensation mechanism while oxygen vacancy generation was constrained. Additionally, the substitution of Ca significantly enhanced the surface basicity, which improved the adsorption and activation ability of CO₂. This study provides valuable applications for the perovskite modification strategies and the efficient CO₂ biomass catalytic gasification.