Green hydrogen production by photocatalytic direct dehydrogenation of methanol on CuPt/TiO2

• Published in: Fuel (Guildford) 2024-06, Vol.366, p.131391, Article 131391
• Main Authors: Zhang, Haifeng, Yang, Xuzhuang, Gao, Guanjun, Liu, Ying, Zhao, Min, Yan, Jingkai, Du, Haoran, Xiao, Xiran, Su, Haiquan
• Format: Article
• Language: English
• Subjects: DFT calculation; Effect of crystal facet; Green hydrogen; Methanol; Photocatalysis
• ISSN: 0016-2361
• DOI: 10.1016/j.fuel.2024.131391

Both experimental and DFT studies demonstrate that the {101} facets of TiO2 exhibit the highest activity for the photocatalytic direct dehydrogenation of methanol to H2, achieving zero carbon emissions. [Display omitted] •The TiO2 {101} facet displays the highest activity for photocatalytic dehydrogenation of CH3OH to H2.•The {101} facet exhibits the lowest energy barrier at each step of the transition states.•The one step route of *CH3O + *CH2O → *HCOOCH3 + *H is impossible.•The {100} facet, having the lowest adsorption energy, promotes CH3OH adsorption.•The TiOx surface from the SMSI enhances methanol adsorption and dissociation. To obtain H2 from methanol under zero carbon emission is a tough challenge. Herein, photocatalytic direct dehydrogenation of methanol to H2 and methyl formate on titania, specifically focusing on the {101}, {100}, and {001} facets supported with CuPt nanoparticles, is investigated by experiment and density functional theory. Our findings reveal that the {100} facets exhibit favorable methanol adsorption characteristics, attributed to their lowest adsorption energy, followed by the {001} and {101} facets. Moreover, methanol adsorbed on the {100} facet readily undergoes conversion to methoxy due to the weakened O-H bond. The formation of surface TiOx resulting from the strong interaction between the support and CuPt nanoparticles proves advantageous for methanol adsorption and dissociation, owing to its low adsorption energy and weakened O-H bond. The pathway from methoxy to methyl formate involves three sequential steps: (1) *CH3O → *CH2O + *H; (2) *CH2O → *CHO + *H; (3) *CH3O + *CHO → HCOOCH3, as opposed to a one-step route of *CH3O + *CH2O → *HCOOCH3 + *H. Remarkably, the {101} facet exhibits the highest catalytic activity among all surfaces, as evidenced by its lowest energy barrier and potential energy at each transition state.