A Cu-ZnO-Al2O3 catalyst with oxygen vacancy for efficient hydrodeoxygenation of lignin-derived guaiacol to hydrocarbons

This study explores the efficacy of a cost-effective Cu-ZnO-Al2O3 catalyst for one-pot hydrodeoxygenation of guaiacol into hydrocarbons. Notably, complete conversion of guaiacol was achieved, yielding a 99.6% hydro-carbon over the robust Cu(6)Zn(3)Al(1) catalyst under the conditions of 4 MPa H2, 300 degrees C, and 8 h with a catalyst/guaiacol ratio of 0.5 g/1.0 g. In-depth catalyst characterizations unveiled the presence of oxygen va-cancies within the ZnO surface layer, acting as pivotal active sites that facilitated the hydrodeoxygenation of guaiacol. Furthermore, Density Functional Theory (DFT) calculations were employed to evaluate several po-tential active sites, revealing that the oxygen vacancy of ZnO on the Cu surface played a crucial role. This va-cancy enhanced the adsorption of intermediate cyclohexanol and markedly reduced the energy barrier for the rate-limiting step. This comprehensive investigation sheds light on the catalytic pathway and offers insights into designing efficient and sustainable biofuel production processes.