The development of highly active and cost-effective metal–organic frameworks (MOFs) with large surface areas, abundant active sites, and distinct structures resulted in reduced kinetic barriers involving a four-electron transfer path for the oxygen evolution reaction (OER). In this work, the OER activity of cobalt–molybdenum metal–organic framework (Co-Mo-MOF)-based materials was significantly improved by controlling 3D and 2D framework structures, namely, Co-Mo-3D and Co-Mo-2D, respectively. When Co-Mo-3D was reacted in an alkaline electrolyte, a highly porous gyroid morphology with a large surface area was formed and designated as KOH-treated Co-Mo-3D. The KOH-treated Co-Mo-3D demonstrated superior OER electrocatalytic activity with a low overpotential of 210 mV at a current density of 10 mA cm–2 and small Tafel slope of 50 mV dec–1 in alkaline solution. In addition, KOH-treated Co-Mo-3D exhibited excellent long-term durability at different voltages. The detailed structure transformation of Co-Mo-MOFs during the reaction was also provided by in situ X-ray diffraction (XRD), X-ray photoemission spectroscopy (XPS), and ex situ X-ray absorption spectroscopy (XAS). Moreover, density functional theory (DFT) calculations revealed that the hydrogen-bonding network system formed in Co-Mo-3D plays an important role in assisting proton transfer and enhancing the catalytic activity of the OER. This work opens up a new prospect for the design and development of catalytically active pillar-layered MOF catalysts for OERs.

Various types of 2D organic–inorganic perovskite solar cells have been developed and investigated due to better electron transport behavior and environmental stability. Controlling the formation of phases in the 2D perovskite films has been considered to play an important role in influencing the stability of perovskite materials and their performance in optoelectronic applications. In this work, Lewis base urea was used as an effective additive for the formation of 2D Ruddlesden—Popper (RP) perovskite (BA)2(MA)n−1PbnI3n+1 thin film with mixed phases (n = 2~4). The detailed structural morphology of the 2D perovskite thin film was investigated by in situ X-ray diffraction (XRD), grazing-incidence small-angle X-ray scattering (GISAXS) and photoluminescence mapping. The results indicated that the urea additive could facilitate the formation of 2D RP perovskite thin film with larger grain size and high crystallinity. The 2D RP perovskite thin films for solar cells exhibited a power conversion efficiency (PCE) of 7.9% under AM 1.5G illumination at 100 mW/cm2.

A new path to the discovery of 2D perovskite structures with metastable phases was demonstrated by using a recrystallization method and the assistance of sulfur-derived organic molecules. Their kinetic formation mechanisms were also investigated.

The high dependence on and high cost of lithium has led to a search for alternative materials. Aluminum ion batteries (AIBs) have gained interest due to their abundance, low cost, and high capacity. However, the use of the expensive 1-ethyl-3-methylimidazolium chloride (EMIC) electrolyte in AIBs curtails its wide application. Recently, high-temperature batteries have also gained much attention owing to their high demand by industries. Herein, we introduce cost-effective 1T molybdenum sulfide grown on SP-1 graphite powder (1T-MoS2/SP-1) as a cathode material for high-temperature AIBs using the AlCl3-urea eutectic electrolyte (1T-MoS2/SP-1–urea system). The AIB using the 1T-MoS2/SP-1–urea system exhibited a capacity as high as 200 mAh/g with high efficiency of 99% over 100 cycles at 60 °C when cycled at the rate of 100 mA/g. However, the AIB displayed a capacity of 105 mAh/g when cycled at room temperature. The enhanced performance of the 1T-MoS2/SP-1–urea system is attributed to reduced viscosity of the AlCl3-urea eutectic electrolyte at higher temperatures with high compatibility of 1T-MoS2 with SP-1. Moreover, the electrocatalytic lithiation of 1T-MoS2 and its effect on the hydrogen evolution reaction were also investigated. We believe that our work can act as a beacon for finding alternative, cost-effective, and high-temperature batteries.