Photothermal-driven Reforming of Methanol Solution into Hydrogen over Ultra-stable Cr-MOF-embedded CuInS₂ Heterostructure

Photothermal-driven reforming of methanol solution to hydrogen (PTRM) is an attractive way for sustainable insitu hydrogen (H-2) supply by solar energy. But the effective activation of MeOH and H2O to improve H-2 production kinetics at low temperatures faces really challenge. As the cleavage energy barrier of C-H bond in methanol is much higher than that of O-H bond dissociation, here, we propose the use of CuInS2 with high interfacial hydroxyl activation capacity to integrate with MIL-101(Cr) matrix via in-situ encapsulation strategy. The pore confinement and site isolation of Cr-MOF matrix (MIL-101(Cr)) keep the high dispersion of CuInS2 (4.20 nm) and prohibit its agglomeration in PTRM. With synergistically photothermal effect, the insertion of CuInS2 not only provides a high-speed channel for photoexcited charge migration through the interface between CuInS2 and MIL-101(Cr) but also enhances the dehydrogenation activity of MeOH and H2O effectively as an electron-enriched tank. Moreover, the excellent ability of CuInS2 to dissociate H2O molecules at low temperature promoted the formation of abundant interfacial center dot OH, which reinforces the C-H bond cleavage of MeOH to decline the apparent activation energy (26%) and boost the H-2 evolution kinetics (36233.0 mu molg(cath)(-1) h(-1)). Encouragingly, CuInS2@MIL-101(Cr) with an exceptional total turnover number (TON) climbing up to 16,775 in 65 h of run without catalyst deactivation. This work provides an important insight for the rational design of ultrastable photo-thermal catalysts toward solar-driven reforming of methanol solution to hydrogen and conducive to the high activity performance in hydrogen-powered polymer electrolyte membrane (PEMFC) fuel cell.