Surface Anchoring and Active Sites of [Mo₃S₁₃]^2– Clusters as Co-Catalysts for Photocatalytic Hydrogen Evolution

Abstract

Achieving light-driven splitting of water with high efficiency remains a challenging task on the way to solar fuel exploration. In this work, to combine the advantages of heterogeneous and homogeneous photosystems, we covalently anchor noble-metal- and carbon-free thiomolybdate [Mo 3 S 13 ] 2– clusters onto photoactive metal oxide supports to act as molecular co-catalysts for photocatalytic water splitting. We demonstrate that strong and surface-limited binding of the [Mo 3 S 13 ] 2– to the oxide surfaces takes place. The attachment involves the loss of the majority of the terminal S 2 2– groups, upon which Mo–O–Ti bonds with the hydroxylated TiO 2 surface are established. The heterogenized [Mo 3 S 13 ] 2– clusters are active and stable co-catalysts for the light-driven hydrogen evolution reaction (HER) with performance close to the level of the benchmark Pt. Optimal HER rates are achieved for 2 wt % cluster loadings, which we relate to the accessibility of the TiO 2 surface required for efficient hole scavenging. We further elucidate the active HER sites by applying thermal post-treatments in air and N 2 . Our data demonstrate the importance of the trinuclear core of the [Mo 3 S 13 ] 2– cluster and suggest bridging S 2 2– and vacant coordination sites at the Mo centers as likely HER active sites. This work provides a prime example for the successful heterogenization of an inorganic molecular cluster as a co-catalyst for light-driven HER and gives the incentive to explore other thio(oxo)metalates.

Combining Highly Dispersed Amorphous MoS3 with Pt Nanodendrites as Robust Electrocatalysts for Hydrogen Evolution Reaction

“…[ 28 ] As shown in the reported MoS species, the valance states of Mo atoms in MoS 2 , Mo 2 S 12 2− , and Mo 3 S 13 2− cluster are all present as Mo 4+ (Figure S7, Supporting Information). [ 29,30 ] We proposed that the polymerization product of MoS 4 2− in our materials is a ‐MoS 3 . Further quantitative analysis of the peak areas showed that the ratio of Mo 5+ to Mo 4+ is about 2:1, which is consistent with the ratio of Mo 5+ to Mo 4+ in the crystal structure of a ‐MoS 3 (Figure 2e).…”

Construction of a heterojunction with fast charge transport channels for photocatalytic hydrogen evolutionviaa synergistic strategy of Co-doping and crystal plane modulation

“…However, effective charge separation and transfer remain decisive factors for photocatalytic hydrogen evolution activity. Various strategies (defect engineering, [4][5][6][7] morphological design, [8][9][10][11] heteroatom doping, [12][13][14][15] loading co-catalysts, [16][17][18] and construction of heterojunctions [19][20][21] ) have been proposed to overcome this pervasive problem present in photocatalysts. Appropriately designed heterostructures can improve the surface reaction kinetics of the catalytic system and thus significantly increase the carrier separation efficiency.…”

Morphology control in the synthesis of [Mo3S13]2−/Co-MOF-74 composite catalysts and their application in the oxygen evolution reaction

“…23 In recent years, [Mo 3 S 13 ] 2À has received increasing attention in many aspects such as hydrogen production and pollutant degradation due to its simple preparation method, low cost and excellent catalytic performance. 24,25 Additionally, [Mo 3 S 13 ] 2À as a co-catalyst has excellent stability in the electrocatalysis, 26 making it a promising nanomaterial. In this work, the shape of Co-MOF-74 can be easily controlled by changing the amount of [Mo 3 S 13 ] 2À (12.5 mg, 35 mg, 70 mg).…”