The grand challenge in the development of atomically dispersed metallic catalysts is their low metal-atom loading density, uncontrollable localization and ambiguous interactions with supports, posing difficulty in maximizing their catalytic performance. Here, we achieve an interface catalyst consisting of atomic cobalt array covalently bound to distorted 1T MoS2 nanosheets (SA Co-D 1T MoS2). The phase of MoS2 transforming from 2H to D-1T, induced by strain from lattice mismatch and formation of Co-S covalent bond between Co and MoS2 during the assembly, is found to be essential to form the highly active single-atom array catalyst. SA Co-D 1T MoS2 achieves Pt-like activity toward HER and high long-term stability. Active-site blocking experiment together with density functional theory (DFT) calculations reveal that the superior catalytic behaviour is associated with an ensemble effect via the synergy of Co adatom and S of the D-1T MoS2 support by tuning hydrogen binding mode at the interface.

A dinuclear cobalt complex [Co (OH)L ](ClO ) (1, L =N[(CH ) NHCH (m-C H )CH NH(CH ) ] N) displays high selectivity and efficiency for the photocatalytic reduction of CO to CO in CH CN/H O (v/v=4:1) under a 450 nm LED light irradiation, with a light intensity of 100 mW cm . The selectivity reaches as high as 98 %, and the turnover numbers (TON) and turnover frequencies (TOF) reach as high as 16896 and 0.47 s , respectively, with the calculated quantum yield of 0.04 %. Such high activity can be attributed to the synergistic catalysis effect between two Co ions within 1, which is strongly supported by the results of control experiments and DFT calculations.

The solar-driven CO 2 reduction is achallenge in the field of "artificial photosynthesis", as most catalysts display low activity and selectivity for CO 2 reduction in watercontaining reaction systems as ar esult of competitive proton reduction. Herein, we report ad inuclear heterometallic complex, [CoZn(OH)L 1 ](ClO 4 ) 3 (CoZn), which shows extremely high photocatalytic activity and selectivity for CO 2 reduction in water/acetonitrile solution. It achieves aselectivity of 98 %for CO 2 -to-CO conversion, with TONa nd TOFv alues of 65000 and 1.8 s À1 ,r espectively,4 ,1 9, and 45-fold higher than the values of corresponding dinuclear homometallic [CoCo-(OH)L 1 ](ClO 4 ) 3 (CoCo), [ZnZn(OH)L 1 ](ClO 4 ) 3 (ZnZn), and mononuclear [CoL 2 (CH 3 CN)](ClO 4 ) 2 (Co), respectively, under the same conditions.T he increased photocatalytic performance of CoZn is due to the enhanced dinuclear metal synergistic catalysis (DMSC) effect between Zn II and Co II , which dramatically lowers the activation barriers of both transition states of CO 2 reduction.

The diversity of electronic characteristics of TMDs ranging from the semiconducting, semi-metallic to metallic have broadened their application in catalysis, electrode materials and next-generation functional electronic devices.

Using first-principles DFT calculations, the pathway and the energy barrier of phase transition between 2H and 1T' have been investigated for MoTe2 and WTe2 monolayers. The Phase transition is controlled by the simultaneous movement of metal atoms and Te atoms in their plane without the intermediate phase 1T. The energy barrier (less than 0.9 eV per formula cell) is not so high that the phase transition is dynamically possible. The relative stability of both 2H and 1T' phases and the energy barrier for phase transition can be modulated by the biaxial and uniaxial strain. The dynamic energy barrier is decreased by applying the strain. The phase transition between 2H and 1T' controlled by the strain can be used to modulate the electronic properties of MoTe2 and WTe2.