Gibbs free energy (ΔG) of water splitting reaction is 237.2 kJ mol −1 , corresponding to a theoretical voltage of 1.23 V. [3] However, the existence of electrochemical/concentration polarization and solution resistance can increase the actual voltage of water electrolysis to much beyond 1.23 V. Particularly, the OER involves a complicated four-electron transfer process, which results in a sluggish kinetics thus has long been the bottleneck. [4] Therefore, it is necessary to explore efficient and robust electrocatalysts to reduce the overpotential of water electrolysis and the extra electric energy consumption. Although noble electrocatalysts, such as Pt, RuO 2 and IrO 2 , are recognized as the most efficient electrocatalysts for water electrolysis, their high scarcity and instability severely impede large-scale applications. [5] Recently, considerable effort has been focused on nonnoble transition-metal materials as viable alternatives for water splitting. Understanding the intrinsic catalytic mechanism and real active sites of these catalysts will benefit the rational design and application of high-efficiency catalysts.With the development of in situ characterization technologies, more reports have revealed that the original electrocatalyst (so-called "pre-catalyst") surface sites would undergo dynamic reconstruction and transform into real reactive species. [6] This in situ reconstruction process could tune the electrocatalytic behaviors such as adsorption, activation, and desorption, thus improving the catalytic performance. [7] On this basis, many researchers utilized the pre-reconstruction of electrocatalysts to obtain a large number of active species for the catalytic reactions. [8] It has been found that the intrinsic properties of the pre-catalysts, such as composition, atomic arrangement, porosity, and crystallinity, would affect the reconstruction rate, reconstruction degree, and catalytic activity of the reconstructed species. [9] Moreover, the reaction conditions also affect the reconstruction process, such as electrochemical operation, applied potential, electrolyte concentration, and pH. [6a] Therefore, tuning the reconstruction process to generate abundant active sites with high intrinsic activity is an effective strategy to boost the catalytic performance of electrocatalysts.Although some influential review articles on the reconstruction of catalysts during water electrolysis have emerged, [10] most of them focus on the discovery and characterization of the reconstruction phenomenon, less on the regulation of the reconstruction process. In addition, reconstructed catalysts for Water electrolysis is regarded as an efficient and green method to produce hydrogen gas, a clean energy carrier that holds the key to solving global energy problems. So far, the efficiency and large-scale application of water electrolysis are restricted by the electrocatalytic activity of applied catalysts. Recently, the reconstruction phenomenon of electrocatalysts during a catalytic reaction has been discovered, which ...

Lack of effective strategies to regulate the internal activity of MoS2 limits its practical application for hydrogen evolution reactions (HERs). Doping of heteroatoms without forming aggregation or an edge enrichment is still challenging, and its effect on the HER needs to be further explored. Herein, a two‐step method is developed to obtain multi‐metal‐doped H‐MoS2, which includes intercalation of the layered MoO3 precursor with a following sulfurization. Benefiting from the capability of the intercalation method to uniformly and simultaneously introduce different elements into the van der Waals gap, this method is universal to obtain multi‐heteroatoms co‐doped MoS2 without forming clusters, phase separation, and an edge enrichment. It is demonstrated that the doping of adjacent cobalt and palladium monomers on MoS2 greatly enhances the HER catalytic activity. The overpotential at 10 mA cm−2 and Tafel slope of Co and Pd co‐doped MoS2 is found to be 49.3 mV and 43.2 mV dec−1, respectively, representing a superior acidic HER catalytic activity. This intercalation‐assisted method also provides a new and general strategy to synthesize uniformly doped transition metal dichalcogenides for various applications.

Surface Reconstruction In article number 2201713, Qiu Jiang, Hanfeng Liang and co‐workers discuss the regulation strategies for surface reconstruction of electrocatalysts. The process, similar to the “Midas Touch” that turns stone into gold, converts pre‐catalysts into highly active species, thus enhancing the overall performance for water splitting.

Heavy Fermion (HF) states emerge in correlated quantum materials due to the intriguing interplay between localized magnetic moments and itinerant electrons but rarely appear in 3d-electron systems due to high itinerancy of d-electrons. Here, an anomalous enhancement of Kondo screening is observed at the Kondo hole of local Fe vacancies in Fe3GeTe2 which is a recently discovered 3d-HF system featuring Kondo lattice and two-dimensional itinerant ferromagnetism. An itinerant Kondo–Ising model is established to reproduce the experimental results and provides insight into the competition between Ising ferromagnetism and Kondo screening. Our work explains the microscopic origin of the d-electron HF states in Fe3GeTe2 and inspires future studies of the enriched quantum many-body effects with Kondo holes.

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Heterostructures of two-dimensional (2D) layered materials with selective compositions play an important role in creating novel functionalities. Effective interface coupling between 2D ferromagnet and electronic materials would enable the generation of exotic physical phenomena caused by intrinsic symmetry breaking and proximity effect at interfaces. Here, epitaxial growth of bilayer Bi(110) on 2D ferromagnetic Fe3GeTe2 (FGT) with large magnetic anisotropy has been reported. Bilayer Bi(110) islands are found to extend along fixed lattice directions of FGT. The six preferred orientations could be divided into two groups of three-fold symmetry axes with the difference approximately to 26°. Moreover, dI/dV measurements confirm the existence of interface coupling between bilayer Bi(110) and FGT. A variation of the energy gap at the edges of bilayer Bi(110) is also observed which is modulated by the interface coupling strengths associated with its buckled atomic structure. This system provides a good platform for further study of the exotic electronic properties of epitaxial Bi(110) on 2D ferromagnetic substrate and promotes potential applications in the field of spin devices.

Oxynitride semiconductors are considered to be promising candidates for solar water splitting. In this work, we show that oxygen-rich SrTaO 2 N has a band gap with direct−indirect character through twin valence-band maximums (VBMs), resulting in good photoelectronic responses. Compared with the direct band gap of ideal SrTaO 2 N, the additional indirect VBM of the oxygen-rich solid solution was found to be due to strontium−oxygen hybridization, using orbital projections based on hybrid/GW density functional theory (DFT). This twin-VBM character was validated by strontium K-edge absorption through extended X-ray absorption fine structure (EXAFS) analysis. The twin-VBM character of the band structure can enhance the photoelectronic response and hole transport. Our findings provide a viable strategy for enhancing the solar water splitting performance of oxynitrides.Article pubs.acs.org/JPCC