The surface reconstruction behavior of transition metal phosphides precursors is considered as an important method to prepare efficient oxygen evolution catalysts, but there are still significant challenges in guiding catalyst design at the atomic scale. Here, the CoP nanowire with excellent water splitting performance and stability is used as a catalytic model to study the reconstruction process. Obvious double redox signals and valence evolution behavior of the Co site are observed, corresponding to Co²⁺/Co³⁺ and Co³⁺/Co⁴⁺ caused by auto-oxidation process. Importantly, the in situ Raman spectrum exhibits the vibration signal of Co–OH in the non-Faradaic potential interval for oxygen evolution reaction, which is considered the initial step in reconstruction process. Density functional theory and ab initio molecular dynamics are used to elucidate this process at the atomic scale: First, OH⁻ exhibits a lower adsorption energy barrier and proton desorption energy barrier at the configuration surface, which proposes the formation of a single oxygen (–O) group. Under a higher –O group coverage, the Co–P bond is destroyed along with the PO_x groups. Subsequently, lower P vacancy formation energy confirm that the Ni-CoP configuration can fast transform into a highly active phase. Based on the optimized reconstruction behavior and rate-limiting barrier, the Ni-CoP nanowire exhibit an excellent overpotential of 1.59 V at 10 mA cm⁻² for overall water splitting, which demonstrates low degradation (2.62%) during the 100 mA cm⁻² for 100 h. This work provide systematic insights into the atomic-level reconstruction mechanism of transition metal phosphides, which benefit further design of water splitting catalysts.

The oxygen evolution reaction (OER) electrocatalysts, which can keep active for a long time in acidic media, are of great significance to proton exchange membrane water electrolyzers. Here, Ru-Co₃O₄ electrocatalysts with transition metal oxide Co₃O₄ as matrix and the noble metal Ru as doping element have been prepared through an ion exchange–pyrolysis process mediated by metal-organic framework, in which Ru atoms occupy the octahedral sites of Co₃O₄. Experimental and theoretical studies show that introduced Ru atoms have a passivation effect on lattice oxygen. The strong coupling between Ru and O causes a negative shift in the energy position of the O p-band centers. Therefore, the bonding activity of oxygen in the adsorbed state to the lattice oxygen is greatly passivated during the OER process, thus improving the stability of matrix material. In addition, benefiting from the modulating effect of the introduced Ru atoms on the metal active sites, the thermodynamic and kinetic barriers have been significantly reduced, which greatly enhances both the catalytic stability and reaction efficiency of Co₃O₄.

Under the complex external reaction conditions, uncovering the true structural evolution of the catalyst is of profound significance for the establishment of relevant structure–activity relationships and the rational design of electrocatalysts. Here, the surface reconstruction of the catalyst was characterized by ex-situ methods and in-situ Raman spectroscopy in CO₂ electroreduction. The final results showed that the Bi₂O₃ nanoparticles were transformed into Bi/Bi₂O₃ two-dimensional thin-layer nanosheets (NSs). It is considered to be the active phase in the electrocatalytic process. The Bi/Bi₂O₃ NSs showed good catalytic performance with a Faraday efficiency (FE) of 94.8% for formate and a current density of 26 mA cm⁻² at −1.01 V. While the catalyst maintained a 90% FE in a wide potential range (−0.91 V to −1.21 V) and long-term stability (24 h). Theoretical calculations support the theory that the excellent performance originates from the enhanced bonding state of surface Bi-Bi, which stabilized the adsorption of the key intermediate OCHO* and thus promoted the production of formate.

Engineering the electronic structure of surface active sites at the atomic level can be an efficient way to modulate the reactivity of catalysts. Herein, we report the rational tuning of surface electronic structure of FePS₃ nanosheets (NSs) by anchoring atomically dispersed metal atom. Theoretical calculations predict that the strong electronic coupling effect in single-atom Ni-FePS₃ facilitates electron aggregation from Fe atom to the nearby Ni-S bond and enhances the electron-transfer of Ni and S sites, which balances the oxygen species adsorption capacity, reinforces water adsorption and dissociation process to accelerate corresponding oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). The optimal Ni-FePS₃ NSs/C exhibits outstanding electrochemical water-splitting activities, delivering an overpotential of 287 mV at the current density of 10 mA cm⁻² and a Tafel slope of 41.1 mV dec⁻¹ for OER; as well as an overpotential decrease of 219 mV for HER compared with pure FePS₃ NSs/C. The concept of electronic coupling interaction between the substrate and implanted single active species offers an additional method for catalyst design and beyond.

In recent years, two-dimensional (2D) layered metal dichalcogenides (MDCs) have received enormous attention on account of their excellent optoelectronic properties. Especially, various MDCs can be constructed into vertical/lateral heterostructures with many novel optical and electrical properties, exhibiting great potential for the application in photodetectors. Therefore, the batch production of 2D MDCs and their heterostructures is crucial for the practical application. Recently, the vapour phase methods have been proved to be dependable for growing large-scale MDCs and related heterostructures with high quality. In this paper, we summarize the latest progress about the synthesis of 2D MDCs and their heterostructures by vapour phase methods. Particular focus is paid to the control of influence factors during the vapour phase growth process. Furthermore, the application of MDCs and their heterostructures in photodetectors with outstanding performance is also outlined. Finally, the challenges and prospects for the future application are presented.

Despite the tremendous efforts devoted to enhancing the activity of oxygen evolution reaction (OER) catalysts, there is still a huge challenge to deeply understand the electronic structure characteristics of transition metal oxide to guide the design of more active catalysts. Herein, Fe₃O₄ with oxygen vacancies (Fe₃O₄-Vac) was synthesized via Ar ion irradiation method and its OER activity was greatly improved by properly modulating the electron density around Fe atoms. The electron density of Fe₃O₄-Vac around Fe atoms increased compared to that of Fe₃O₄ according to the characterization of synchrotron-based X-ray absorption near-edge structure (XANES), extended X-ray absorption fine structure (EXAFS) spectra, and density functional theory (DFT) calculation. Moreover, the DFT results indicate the enhancement of the desorption of HOO* groups which significantly reduced the OER reaction barrier. Fe₃O₄-Vac catalyst shows an overpotential of 353 mV, lower than that of FeOOH (853 mV) and Fe₃O₄ (415 mV) at 10 mA cm⁻², and a low Tafel slope of 50 mV dec⁻¹ in 1 M KOH, which was even better than commercial RuO₂ at high potential. This modulation approach provides us with valuable insights for exploring efficient and robust water-splitting electrocatalysts.

In this paper, we report a method to change the threshold voltage of SnO₂ and In₂O₃ nanowire transistors by Ga⁺ ion irradiation. Unlike the results in earlier reports, the threshold voltages of SnO₂ and In₂O₃ nanowire field-effect transistors (FETs) shift in the negative gate voltage direction after Ga⁺ ion irradiation. Smaller threshold voltages, achieved by Ga⁺ ion irradiation, are required for high-performance and low-voltage operation. The threshold voltage shift can be attributed to the degradation of surface defects caused by Ga⁺ ion irradiation. After irradiation, the current on/off ratio declines slightly, but is still close to ~10⁶. The results indicate that Ga⁺ ion beam irradiation plays a vital role in improving the performance of oxide nanowire FETs.