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 in-situ hydrogen (H2) supply by solar energy. But the effective activation of MeOH and H2O to improve H2 production kinetics at low temperatures faces really challenge. As the cleavage energy barrier of CH bond in methanol is much higher than that of OH 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 OH, which reinforces the CH bond cleavage of MeOH to decline the apparent activation energy (26%) and boost the H2 evolution kinetics (36233.0 μmolgcat-1h−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 ultra-stable 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.