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Metal-free catalysts offer a desirable alternative to traditional metal-based catalysts. However, it remains challenging to improve the catalytic performance of metal-free catalysts to be as promising as that of metal-based materials. Herein, a polymer-assisted method followed by pyrolysis treatment was employed to synthesize nitrogen (N)-doped porous carbon nanoflowers with nanosheet subunits. Leveraging the unique geometry structure and abundant pyridinic-N active sites, the optimized catalyst exhibits a good half-wave potential of 0.85 V versus reversible hydrogen electrode (vs. RHE) and long-term stability with only 17.0 mV negative shift of the half-wave potential after 10 000 cyclic voltammetry cycles in alkaline electrolyte. This research presents a viable strategy for advancing metal-free catalysts. [ABSTRACT FROM AUTHOR]

Understanding the relationship between electrocatalytic performance and local structure at the molecular level is of great significance. Herein, a bifunctional electrocatalyst CuCA (CA = chloranilate) is constructed for both nitrogen reduction reaction (NRR) and nitrate reduction reaction (NO3RR). Combined structural analyses using Rietveld refinement, extended X‐ray adsorption fine structure (EXAFS), and pair distribution function (PDF) revealed a significant distortion of the Cu‐O4 structure. Benefitting from the unique local structure, Cu‐CA shows an impressive NH3 yield rate of 286.00 ug h−1 mg−1 (FE = 18.25%, ‐0.85 V vs RHE), 3180.00 ug h−1 mg−1 (FE = 90.3%, ‐0.9 V vs RHE) for NRR and NO3RR, respectively. In contrast, the pyrazine (Pyz) decorated compound Cu‐CA‐Pyz with a less distorted Cu‐O4 structure and fewer active sites show much lower activity. Density functional theory (DFT) calculations shed light on that the distorted nature can effectively regulate the electron density distribution, which can lower the energy barrier of adsorption and activation of the intermediate species, leading to the enhanced activity. These findings may give new insight into the structural‐property relationship and open up opportunities for the exploration of efficient electrocatalysts. [ABSTRACT FROM AUTHOR]

A carbon nano-onion structure with interconnected graphitic layers has been demonstrated as a high-performance supercapacitor electrode material. However, the structure suffers from a low specific surface area (SSA), which limits its further performance improvement. Herein, we use CO2 thermal activation to tune the pore structure of the interconnected carbon nano-onions (IHCNOs) for efficiently improving the energy storage performances. The activated IHCNOs (A-IHCNOs) exhibit a high SSA of 1087.6 m2 g–1, high volumes of micropores (0.11 cm3 g–1) and mesopores (1.89 cm3 g–1), high graphitic crystallinity, and excellent wettability to ionic liquids (ILs), while maintaining the structural advantages of interconnected graphitic layers. As a result, the supercapacitor device based on A-IHCNOs in a neat IL electrolyte exhibits a high specific capacitance of 92 F g–1 at 1 A g–1, corresponding to a high energy density of 204.4 Wh kg–1. An ultrahigh power density of 400 kW kg–1 can be achieved with a high energy density of 51.9 Wh kg–1 still maintained. Moreover, the supercapacitors show excellent cycling stabilities in different IL electrolytes. This study demonstrates a green and sustainable CO2 activation as an efficient strategy for simultaneously keeping the double-layer capacitive behavior and improving the supercapacitive energy storage performance of the carbon structures. [ABSTRACT FROM AUTHOR]

Background: The involvement of cytotoxic CD4+ T cells (CD4+ CTLs) and their potential role in dictating the response to immune checkpoint inhibitors (ICIs) in patients with metastatic renal cell carcinoma (mRCC) remains an unexplored area of research. Methods: Utilizing single-cell RNA sequencing, we analyzed the immunophenotype and expression patterns of CD4+ T lymphocyte subtypes in mRCC patients, followed by preliminary validation via multi-immunofluorescent staining. In addition, we obtained a comprehensive immunotherapy dataset encompassing single-cell RNA sequencing datasets and bulk RNA-seq cohorts from the European Genome-Phenome Archive and ArrayExpress database. Utilizing the CIBERSORTx deconvolution algorithms, we derived a signature score for CD4+ CTLs from the bulk-RNA-seq datasets of the CheckMate 009/025 clinical trials. Results: Single-cell analysis of CD4+ T lymphocytes in mRCC reveals several cancer-specific states, including diverse phenotypes of regulatory T cells. Remarkably, we observe that CD4+ CTLs cells constitute a substantial proportion of all CD4+ T lymphocyte sub-clusters in mRCC patients, highlighting their potential significance in the disease. Furthermore, within mRCC patients, we identify two distinct cytotoxic states of CD4+ T cells: CD4+GZMK+ T cells, which exhibit a weaker cytotoxic potential, and CD4+GZMB+ T cells, which demonstrate robust cytotoxic activity. Both regulatory T cells and CD4+ CTLs originate from proliferating CD4+ T cells within mRCC tissues. Intriguingly, our trajectory analysis indicates that the weakly cytotoxic CD4+GZMK+ T cells differentiate from their more cytotoxic CD4+GZMB+ counterparts. In comparing patients with lower CD4+ CTLs levels to those with higher CD4+ CTLs abundance in the CheckMate 009 and 25 immunotherapy cohorts, the latter group exhibited significantly improved OS and PFS probability. Conclusion: Our study underscores the pivotal role that intratumoral CD4+ CTLs may play in bolstering anti-tumor immunity, suggesting their potential as a promising biomarker for predicting response to ICIs in patients with mRCC. [ABSTRACT FROM AUTHOR]