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Electrochemical water splitting produces clean hydrogen fuel as one of the pivotal alternative energies to fossil fuels in the near future. However, the anodic oxygen evolution reaction (OER) is a significant bottleneck that curtails large-scale applications of electrochemical water splitting technology, owing to its sluggish reaction kinetics. In the past few decades, various methods have been proposed to improve the OER kinetics. Among them, doping is a simple and efficient method to mold the OER kinetics of a catalyst by incorporating different or hetero atoms into the host lattice. These efforts are vital to design highly efficient OER catalysts for real-world applications. However, the OER mechanism of a doped catalyst varies, depending on the host lattice and the dopant. This review highlights different doping strategies and associated OER mechanisms of state-of-the-art catalysts, including oxides (noble metal oxides, perovskite oxides, spinel oxides, hydroxides and others), non-oxides (metal sulfides, metal selenides, metal phosphides, metal nitrides and metal carbides), and carbon-based catalysts (graphene, carbon nanotubes and others). Fundamental understanding of the doping effects on the OER from combined experimental and theoretical research provides guidelines for designing efficient catalysts. 

Organometal halides are promising materials for photovoltaic applications, offering tunable electronic levels, excellent charge transport, and simplicity of thin-film device fabrication. Two-dimensional (2D) perovskites have emerged as promising candidates over three-dimensional (3D) ones due to their interesting optical and electrical properties. However, maximizing the power conversion efficiency is a critical issue to improve the performance of these solar cells. In this work, we studied the photophysics of a two-dimensional (2D) perovskite (CH3NH3)2Pb(SCN)2I2 thin film using steady-state and time-resolved absorption and emission spectroscopy and compared it with the three-dimensional (3D) counterpart CH3NH3PbI3. We observed a higher bandgap and faster charge recombination in (CH3NH3)2Pb(SCN)2I2 compared to CH3NH3PbI3. This work provides an improved understanding of fundamental photophysical processes in perovskite structures and provides the guideline for the design, synthesis, and fabrication of solar cells. 

Two-dimensional materials based on transition metal carbides have been intensively studied due to their unique properties including metallic conductivity, hydrophilicity and structural diversity and have shown a great potential in several applications, for example, energy storage, sensing and optoelectronics. While MXenes based on magnetic transition elements show interesting magnetic properties, not much is known about the magnetic properties of titanium-based MXenes. Here, we measured the magnetic properties of Ti3C2Tx MXenes synthesized by different chemical etching conditions such as etching temperature and time. Our magnetic measurements were performed in a superconducting quantum interference device (SQUID) vibrating sample. These data suggest that there is a paramagnetic-antiferromagnetic (PM-AFM) phase transition and the transition temperature depends on the synthesis procedure of MXenes. Our observation indicates that the magnetic properties of these MXenes can be tuned by the extent of chemical etching, which can be beneficial for the design of MXenes-based spintronic devices.