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Soft X-ray imaging is a powerful tool to explore the structure of cells, probe material with nanometer resolution, and investigate the energetic phenomena in the universe. Conventional soft X-ray image sensors are by and large Si-based charge coupled devices that suffer from low frame rates, complex fabrication processes, mechanical inflexibility, and required cooling below -60 °C. Here, a soft X-ray photodiode is reported based on low-cost metal halide perovskite with comparable performance to commercial Si-based device. Nanothrough network electrode minimized the optical loss due to the shadowing of insensitive layers, while a multidimensional perovskite heterojunction is generated to reduce the photo-generated carrier loss. This strategy promoted a record quantum efficiency of 8 × 103% without cooling, several orders of magnitude greater than the previously achieved. Flexible and curved soft X-ray imaging arrays are fabricated based on this high-performance device structure, demonstrating stable soft X-ray response and sharp imaging capabilities. This work highlights the low-cost and efficient perovskite photodiode as a strong candidate for the next-generation soft X-ray image sensors.

High-quality perovskite films are essential for achieving high performance of optoelectronic devices; However, solution-processed perovskite films are known to suffer from compositional and structural inhomogeneity due to lack of systematic control over the kinetics during the formation. Here, the microscopic homogeneity of perovskite films is successfully enhanced by modulating the conversion reaction kinetics using a catalyst-like system generated by a foaming agent. The chemical and structural evolution during this catalytic conversion is revealed by a multimodal synchrotron toolkit with spatial resolutions spanning many length scales. Combining these insights with computational investigations, a cyclic conversion pathway model is developed that yields exceptional perovskite homogeneity due to enhanced conversion, having a power conversion efficiency of 24.51% for photovoltaic devices. This work establishes a systematic link between processing of precursor and homogeneity of the perovskite films.

The metal–support interaction of heterogeneous catalysts has garnered significant attention due to its role in boosting electrocatalytic efficiency. Herein, we synthesized uniformly dispersed Pt nanoparticles decorated on a MoOx support by an ultrafast flash joule heating method. This method enables the simultaneous loading of metal and modification of support structures in a controllable, ultrafast manner. The optimal catalyst demonstrates exceptional performance in the hydrogen evolution reaction (HER) under acidic conditions, characterized by a low overpotential of only 55.08 mV to achieve a current density of 100 mA cm−2, a Tafel slope of 19.94 mV dec−1, and a significant mass activity of 13.80 A mgPt−1 at 50 mV vs. RHE. In addition, the optimal catalyst exhibits better stability for the HER than a commercial 20 wt% Pt/C catalyst. The spectroscopic characterization confirms the charge transfer between the metal and support, leading to a near-zero valence state of Pt in the optimal catalyst. Density functional theory calculations further corroborate that the metal–support interaction between Pt and MoOx leads to a suitable hydrogen adsorption free energy at the interfacial Pt site, which results in accelerating the reaction kinetics of the HER. This work aims to design and develop a metal–support heterostructure with high HER activity and stability, and provides a strategy for engineering crystalline structures and electronic configurations using an ultrafast flash Joule heating synthesis method. [ABSTRACT FROM AUTHOR]

Selective catalytic reduction of NO by CO is challenging in environmental catalysis but attractive owing to the advantage of simultaneous elimination of NO and CO. Here, model catalysts consisting of Pd nanoparticles (NPs) and single-atom Pd supported on a CeO2 (111) film grown on Cu (111) (denoted as Pd NPs/CeO2 and Pd1/CeO2, respectively) were successfully prepared and characterized by synchrotron radiation photoemission spectroscopy (SRPES) and infrared reflection absorption spectroscopy (IRAS). The NO + CO adsorption/reaction on the Pd1/CeO2 and Pd NPs/CeO2 catalysts were carefully investigated using SRPES, temperature-programmed desorption (TPD), and IRAS. It is found that the reaction products on both model catalysts are in good agreement with those on real catalysts, demonstrating the good reliability of using these model catalysts to study the reaction mechanism of the NO + CO reaction. On the Pd NPs/CeO2 surface, N2 is formed by the combination of atomic N coming from the dissociation of NO on Pd NPs at higher temperatures. N2O formation occurs probably via chemisorbed NO combined with atomic N on the surface. While on the single-atom Pd1/CeO2 surface, no N2O is detected. The 100% N2 selectivity may stem from the formation of O-N-N-O* intermediate on the surface. Through this study, direct experimental evidence for the reaction mechanisms of the NO + CO reaction is provided, which supports the previous density functional theory (DFT) calculations. [ABSTRACT FROM AUTHOR]

Developing highly efficient, selective and low-overpotential electrocatalysts for carbon dioxide (CO2) reduction is crucial. This study reports an efficient Ni single-atom catalyst coordinated with pyrrolic nitrogen and pyridinic nitrogen for CO2 reduction to carbon monoxide (CO). In flow cell experiments, the catalyst achieves a CO partial current density of 20.1 mA cmgeo−2 at −0.15 V vs. reversible hydrogen electrode (VRHE). It exhibits a high turnover frequency of over 274,000 site−1 h−1 at −1.0 VRHE and maintains high Faradaic efficiency of CO (FECO) exceeding 90% within −0.15 to −0.9 VRHE. Operando synchrotron-based infrared and X-ray absorption spectra, and theoretical calculations reveal that mono CO-adsorbed Ni single sites formed during electrochemical processes contribute to the balance between key intermediates formation and CO desorption, providing insights into the catalyst's origin of catalytic activity. Overall, this work presents a Ni single-atom catalyst with good selectivity and activity for CO2 reduction while shedding light on its underlying mechanism. Rational design of electrocatalysts for selective CO2 conversion is of great interests. Here the authors show that Ni single atom with asymmetric pyrrolic and pyridinic nitrogen for efficient CO2 electroconversion to CO. [ABSTRACT FROM AUTHOR]