Mechanistic investigation of hydrogen production from methanol by aqueous phase reforming over Ni/AC catalyst

As a clean energy source, hydrogen has attracted wide attention due to its advantages of renewability, high energy density and no pollution. Methanol has a hydrogen content of 12.6 wt%, which is an ideal source for H 2 production. In this study, FactSage software was used to simulate methanol aqueous phase reforming (APR) reaction for H 2 production. Thermodynamic analysis based on the Gibbs free energy minimization method indicated that methanol decomposition required a threshold temperature of 230−240 °C, which was also promoted the water gas shift (WGS) reaction. Based on the optimal H 2 production temperature obtained by simulation, the effect of methanol to water molar ratio on H 2 production was investigated. Under the optimal methanol to water molar ratio, the effects of reaction temperature and Ni/AC catalyst on H 2 production were investigated. It was found that the simulation results were consistent with the experimental results without catalyst under the condition of constant temperature and constant volume. At 240 °C, the methanol to water molar ratio of 4: 3 was beneficial to the forward WGS. The H 2 yield reached a peak of 41.9 mmol/L under the conditions of 240 °C, 10Ni/AC, methanol to water molar ratio of 6: 3 and reaction time of 1 h. Combined with density functional theory (DFT) calculation, the adsorption models of methanol and reaction intermediates (∗CH 2 O, ∗HCOOH) on the oxygen vacancy of C–O bond on Ni/AC were constructed. The mechanism of methanol APR, with methanol decomposition as the primary reaction and WGS as the secondary reaction, offers theoretical support for H 2 production from methanol APR.