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Exposing and stabilizing undercoordinated platinum (Pt) sites and therefore optimizing their adsorption to reactive intermediates offers a desirable strategy to develop highly efficient Pt-based electrocatalysts. However, preparation of atomically controllable Pt-based model catalysts to understand the correlation between electronic structure, adsorption energy, and catalytic properties of atomic Pt sites is still challenging. Herein we report the atomically thin two-dimensional PtTe2 nanosheets with well-dispersed single atomic Te vacancies (Te-SAVs) and atomically well-defined undercoordinated Pt sites as a model electrocatalyst. A controlled thermal treatment drives the migration of the Te-SAVs to form thermodynamically stabilized, ordered Te-SAV clusters, which decreases both the density of states of undercoordinated Pt sites around the Fermi level and the interacting orbital volume of Pt sites. As a result, the binding strength of atomically defined Pt active sites to H intermediates is effectively reduced, which renders PtTe2 nanosheets highly active and stable in hydrogen evolution reaction.

Monolayer WS has interesting properties as a direct bandgap semiconductor, photocatalyst, and electrocatalyst, but it is still a significant challenge to prepare this material in colloidal form by liquid-phase exfoliation (LPE). Here, we report the preparation of 1-2 layer semiconducting WS nanosheets in a yield of 18-22 wt % by a modified LPE method that involves preintercalation with substoichometric quantities of n-butyllithium. The exfoliated WS nanosheeets are n-type, have a bandgap of ∼1.78 eV, and act as a cocatalyst with CdS nanorods in photocatalytic hydrogen evolution using lactate as a sacrificial electron donor. Up to a 26-fold increase in H evolution rate was observed with WS/CdS hybrids compared with their pure CdS counterpart, and an absorbed photon quantum yield (AQE) of >60% was measured with the optimized photocatalyst.

SYNOPSIS: A facile approach was developed to produce TiO 2 NAs/MoS 2 3D photoanode with different phases (1T or 2H) of MoS 2 for photoelectrochemical water splitting.ABSTRACT: A novel three-dimensional (3D) photoanode with exfoliated MoS 2 nanosheets on the TiO 2 nanorod arrays (TiO 2 NAs) was successfully fabricated by combining hydrothermal and drop-casting methods. The influences of the different phases (1T and 2H) of the MoS 2 nanosheets on the photoelectrochemical (PEC) performances of such a TiO 2 NAs/MoS 2 3D system have been systematically investigated. Parallel experiments revealed that the TiO 2 NAs/1T-MoS 2 composite with optimized 1T-MoS 2 loading exhibited the highest photo-electric conversion efficiency, which was about 440% and 93% higher than those of the TiO 2 NAs and the TiO 2 NAs/2H-MoS 2 counterpart, respectively. The enhanced catalytic performances of the TiO 2 NAs/1T-MoS 2 composite can be attributed to the superior conductivity of 1T-MoS 2 and the strong interaction between TiO 2 NAs and 1T-MoS 2 . The photo-generated holes can therefore transfer from the TiO 2 NAs to the 1T-MoS 2 , thus leading to enhanced charge separation efficiency.(2) May, M. M.; Lewerenz, H.-J.; Lackner, D.; Dimroth, F.; Hannappel, T., Efficient direct solar-to-hydrogen conversion by in situ interface transformation of a tandem structure. Nat. Commun. 2015, 6, 8286, DOI 10.1038/ncomms9286. (3) Hisatomi, T.; Kubota, J.; Domen, K., Recent advances in semiconductors for photocatalytic and photoelectrochemical water splitting. Chem. Soc. Rev. 2014, 43, 7520-7535, DOI 10.1039/c3cs60378d. (4) Han, H. S.; Han, G. S.; Kim, J. S.; Kim, D. H.; Hong, J. S.; Caliskan, S.; Jung, H. S.; Cho, I. S.; Lee, J. K., Indium-tin-oxide nanowire array based CdSe/CdS/TiO 2 one-dimensional oxygen vacancy concentration, and photocatalytic activity. J. Am. Chem. Soc. 2012, 134, 6751-6761, DOI 10.1021/ja300823a. (18) Qin, D.-D.; Bi, Y.-P.; Feng, X.-J.; Wang, W.; Barber, G. D.; Wang, T.; Song, Y.-M.; Lu, X.-Q.; Mallouk, T. E., Hydrothermal growth and photoelectrochemistry of highly oriented, crystalline anatase TiO 2 nanorods on transparent conducting electrodes. Chem. Mater. 2015, 27, 4180-4183, DOI 10.1021/acs.chemmater.5b00782. (19) Zegeye, T. A.; Kuo, C.-F. J.; Wotango, A. S.; Pan, C.-J.; Chen, H.-M.; Haregewoin, A. M.; Cheng, J.-H.; Su, W.-N.; Hwang, B.-J., Hybrid nanostructured microporous carbonmesoporous carbon doped titanium dioxide/sulfur composite positive electrode materials for rechargeable lithium-sulfur batteries. (20) Agegnehu, A. K.; Pan, C.-J.; Tsai, M.-C.; Rick, J.; Su, W.-N.; Lee, J.-F.; Hwang, B. J., Visible light responsive noble metal-free nanocomposite of V-doped TiO 2 nanorod with highly reduced graphene oxide for enhanced solar H 2 production. Int. J. Hydrogen Energ. 2016, 41, 6752-6762, DOI 10.1016/j.ijhydene.2016.03.025. (21) Asahi, R.; Morikawa, T.; Ohwaki, T.; Aoki, K.; Taga, Y., Visible-light photocatalysis in nitrogen-doped titanium oxides. Sun, W.-T.; Yu, Y.; Pan, H.-Y.; Gao, X.-F.; Chen, Q.; Peng, L.-M., CdS quant...

Metal phosphides are promising efficient non-Pt electrocatalysts for hydrogen evolution reaction (HER). Herein, we report a simple strategy to controllably synthesize pure RuP and RuP 2 and evaluate their HER performances in all pH range. Different from other transition metal phosphides, the HER performance of the RuP x in all pH range obviously improves as the phosphorus content decreases. By systematic research, it has been found that the RuP-475 with more Ru had much better conductivity and more catalytically active sites than the P rich RuP 2 -550. In addition, the RuP-475 exhibits excellent HER performance with small overpotential at a current density of 10 mA cm −2 (46, 47, 22 mV in pH 0, 7, and 14, respectively).

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The direct functionalization of C(sp3)–H bonds is an attractive research topic in organic synthetic chemistry. The cross-dehydrogenative coupling (CDC) reaction provides a simple and powerful tool for the construction of C–C and C–heteroatom bonds. Recently, some progress has been made in the iron-catalyzed aerobic oxidative CDC reactions. Here, we present recent developments in the direct functionalization of C(sp3)–H bonds catalyzed by simple iron salts with molecular oxygen as the terminal oxidant.1 Introduction2 C(sp3)–C Bond Formation3 C(sp3)–N Bond Formation4 C(sp3)–S(Se) Bond Formation5 Conclusion and Outlook

Poly(N-isopropylacrylamide) (PNIPAM) is broadly applicable in many fields due to its temperature-induced phase transition property. Herein, a facile method to incorporate exfoliated Ti2C3Tx nanosheets in the PNIPAM network is reported. Due to compatibility, stability and photothermal properties of the incorporated Ti2C3Tx nanosheets, the obtained MXene/PNIPAM composite hydrogel shows excellent photothermal properties, expanding the pure thermal-responsive property of the PNIPAM hydrogel. Based on the smart composite hydrogel, remote light-control of the microfluidic pipeline is also demonstrated.