Kaihong Chen

The production of solar fuels directly from atmospheric CO2 remains a long-standing goal, primarily because catalysts perform poorly under highly dilute CO2 (approximately 420 ppm) and in the presence of oxygen. Herein, we report a molecular activation strategy that simultaneously enriches the local CO2 concentration and tunes the electronic structure of active sites by integrating basic organic ligands into cobalt-doped MoS2 (MoS2:Co). Density functional theory (DFT) calculations reveal that ligand basicity governs both CO2 adsorption capacity and metal–ligand interactions, enabling precise control over catalytic activity. This synergy, achieved by integrating a ligand of moderate basicity, i.e., 2-methylimidazole (2-MIm), onto the surface of MoS2:Co, results in an over 1800-fold enhancement in formic acid production with >99% selectivity in pure water and without sacrificial agents. Notably, the system can also operate under ambient air and natural sunlight, producing formic acid continuously for five days without external CO2 supply. In situ spectroscopy and DFT calculations underlie the essential role of 2-MIm in enhancing CO2 reduction kinetics by modulating the electronic structure of Co dopants, facilitating electron transfer, and stabilizing intermediates. By effectively bypassing the need for energy-intensive direct air capture, this work establishes a robust and viable pathway for developing decentralized solar refineries that convert air directly into solar fuels.

Fluorinated covalent organic frameworks (COFs) exhibited exceptional activity for visible-light-driven CO₂ reduction to syngas with tunable product selectivity.

A long-standing trade-off exists between improving crystallinity and minimizing particle size in the synthesis of perovskite-type transition-metal oxynitride photocatalysts via the thermal nitridation of commonly used metal oxide and carbonate precursors. Here, we overcome this limitation to fabricate ATaO₂N (A = Sr, Ca, Ba) single nanocrystals with particle sizes of several tens of nanometers, excellent crystallinity and tunable long-wavelength response via thermal nitridation of mixtures of tantalum disulfide, metal hydroxides (A(OH)₂), and molten-salt fluxes (e.g., SrCl₂) as precursors. The SrTaO₂N nanocrystals modified with a tailored Ir–Pt alloy@Cr₂O₃ cocatalyst evolved H₂ around two orders of magnitude more efficiently than the previously reported SrTaO₂N photocatalysts, with a record solar-to-hydrogen energy conversion efficiency of 0.15% for SrTaO₂N in Z-scheme water splitting. Our findings enable the synthesis of perovskite-type transition-metal oxynitride nanocrystals by thermal nitridation and pave the way for manufacturing advanced long-wavelength-responsive particulate photocatalysts for efficient solar energy conversion.

Solar-driven water splitting based on particulate semiconductor materials is studied as a technology for green hydrogen production. Transition-metal (oxy)nitride photocatalysts are promising materials for overall water splitting (OWS) via a one- or two-step excitation process because their band structure is suitable for water splitting under visible light. Yet, these materials suffer from low solar-to-hydrogen energy conversion efficiency (STH), mainly because of their high defect density, low charge separation and migration efficiency, sluggish surface redox reactions, and/or side reactions. Their poor thermal stability in air and under the harsh nitridation conditions required to synthesize these materials makes further material improvements difficult. Here, we review key challenges in the two different OWS systems and highlight some strategies recently identified as promising for improving photocatalytic activity. Finally, we discuss opportunities and challenges facing the future development of transition-metal (oxy)nitride-based OWS systems.

The development of narrow-bandgap photocatalysts for one-step-excitation overall water splitting (OWS) remains a critical challenge in the field of solar hydrogen production. SrTaO₂N is a photocatalytic material having a band structure suitable for OWS under visible light (λ ≤ 600 nm). However, the presence of defects in the oxynitride and the lack of cocatalysts to promote simultaneous hydrogen and oxygen evolution make it challenging to realize OWS using this material. The present work demonstrates a SrTaO₂N-based particulate photocatalyst for OWS. This photocatalyst, which was composed of single crystals, was obtained by nitriding SrCl₂ and Ta₂O₅ together with NaOH, with the latter added to control the formation of defects. The subsequent loading of bimetallic RuIrO_x nanoparticles accelerated charge separation and allowed the SrTaO₂N photocatalyst to exhibit superior OWS activity. This research presenting the strategies of controlling the oxygen sources and promoting the cocatalyst function is expected to expand the range of potential OWS-active oxynitride photocatalysts and permit the design of efficient cocatalysts for photocatalytic OWS.

Background: Although inflammation is a known predictor for poor prognosis in patients with diabetics, few data report the synergistic association between inflammation, malnutrition, and mortality in patients with diabetics. We aim to explore whether malnutrition modifies the predictor of inflammation on prognosis.Methods: Nutritional status and inflammation were measured in 6,682 patients with diabetics undergoing coronary angiography or percutaneous coronary intervention between January 2007 to December 2018 from Cardiorenal Improvement Registry. Malnutrition was defined as Controlling Nutritional Status (CONUT) score, which was more than 1. High-sensitivity C-reactive protein (hs-CRP) exceeding the median was assessed as a high-risk inflammation. Cox regression models were used to estimate hazard ratios (HR) for mortality across combined hs-CRP and CONUT score categories.Results: During a median follow-up of 5.0 years (interquartile range: 3.0–7.6 years), 759 (11.36%) patients died. The mortality of the four groups (normal nutrition and low hs-CRP level; normal nutrition and high hs-CRP level; malnutrition and low hs-CRP level; and malnutrition and high hs-CRP level) were 7.29, 7.12, 10.71, and 17.31%, respectively. Compared with normal nutrition and low hs-CRP level, an isolated condition of either malnutrition or high hs-CRP level was not associated with any significant risk for all-cause mortality. However, concomitant presence of both high hs-CRP level and malnutrition condition was associated with a significantly increased risk of all-cause mortality (HR: 1.51; 95% CI: 1.20–1.89; p < 0.001). The p-value for interaction between nutritional status and hs-CRP level on all-cause mortality was 0.03.Conclusion: The interplay of inflammation and malnutrition in patients with diabetics significantly amplifies the deleterious effects of each as distinct disease entities. A prospective randomized clinical trial is needed in the future to verify the results.

A triblock amphiphilic polymer derived from the copolymerization of CO₂ and epoxides containing a bipyridine rhenium complex in its backbone is shown to effectively catalyze the visible‐light‐driven reduction of CO₂ to CO. This polymer provides uniformly spherical micelles in aqueous solution, where the metal catalyst is sequestered in the hydrophobic portion of the nanostructured micelle. CO₂ to CO reduction occurs in an efficient visible‐light‐driven process in aqueous media with turnover numbers up to 110 (>99 % selectivity) in the absence of a photosensitizer, which is a 37‐fold enhancement over the corresponding molecular rhenium catalyst in organic solvent. Notably, the amphiphilic polycarbonate micelle rhenium catalyst suppresses H₂ generation, presumably by preventing deactivation of the active catalytic center by water.

A triblock amphiphilic polymer derived from the copolymerization of CO₂ and epoxides containing a bipyridine rhenium complex in its backbone is shown to effectively catalyze the visible‐light‐driven reduction of CO₂ to CO. This polymer provides uniformly spherical micelles in aqueous solution, where the metal catalyst is sequestered in the hydrophobic portion of the nanostructured micelle. CO₂ to CO reduction occurs in an efficient visible‐light‐driven process in aqueous media with turnover numbers up to 110 (>99 % selectivity) in the absence of a photosensitizer, which is a 37‐fold enhancement over the corresponding molecular rhenium catalyst in organic solvent. Notably, the amphiphilic polycarbonate micelle rhenium catalyst suppresses H₂ generation, presumably by preventing deactivation of the active catalytic center by water.