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Methane (CH4) and hydrogen (H2) show promise as low-carbon energy sources, but their impurities, including H2 and CO, pose challenges for storage and use. To address these challenges, a robust purification protocol for CH4 and/or H2, combined with the catalytic conversion of impurities into CO2 and H2O, is a compelling solution. In this work, we investigated 11 phosphotungstic acid (PTA)-supported single-atom catalysts (SACs) by density functional theory (DFT) computations. Os1/PTA SACs exhibited superior catalytic activity, and the ease of oxidation follows the CO > H2 > CH4 order. It facilitated efficient purification of CH4 in solvents such as water, MeOH, and various others. For H2 purification, Os1/PTA SACs demonstrated excellent performance in gas, water, and MeOH. Notably, in water and MeOH, it selectively removed CO without consuming H2 with low free energy barriers. The strong Os-PTA interactions and charge transfer mechanism contributed to its exceptional catalytic activity. Our findings shed light on SAC behavior and their potential for efficient CH4 and H2 purification. By addressing impurity challenges and improving clean energy utilization, these findings contribute to the development of sustainable energy technologies. [ABSTRACT FROM AUTHOR]

Furfural (C5H4O2) is an important platform chemical for the synthesis of next-generation bio-fuels. Herein, we report a novel and reusable heterogeneous catalyst, Pd-PdO/ZnSO4 with 1.1 mol% palladium (Pd), for the production of furfural by flash pyrolysis of lignocelluloses at 400 °C. For both dry and wet C6 cellulose and its monomers, the furfural yields reach 74–82 mol%, relative to 96 mol% from C5 xylan and 23–33 wt% from sugarcane bagasse and corncob. The catalyst has a well-defined structure and bifunctional property, comprising a ZnSO4 support for the dehydration and isomerization of glucose, and a local core-shell configuration for metallic Pd0 encapsulated by an oxide (PdO) layer. The PdO layer is active for the Grob fragmentation of formaldehyde (HCHO) from glucose, which is subsequently in-situ steam reformed into syn-gas (i.e. H2 and CO), whereas the Pd0 core is active in promoting the last dehydration step for the formation of furfural. Furfural is an important platform chemical for the synthesis of next-generation bio-fuels. Here the authors report a novel heterogeneous catalyst, Pd-PdO/ZnSO4, for the mass production of furfural from catalytic flash pyrolysis of lignocellulosic biomasses. [ABSTRACT FROM AUTHOR]

Graphene‐like borophene was theoretically proposed and recently synthesized on Al (111) surface, however, how to conquer its structural instability is still an open question. By means of density functional theory computations, we theoretically predicted that honeycomb borophene can be well stabilized by double‐sided surface passivation with monovalent functional groups (X = F, Cl, Br, I, OH, and NH2) due to the electron redistributions. The system undergoes the transition from metallic to semiconducting upon functionalization, while the energy gap depends on the choice of functional groups. Under external strain, the gap values can be manipulated over a broad range. Our further calculations indicated that the functionalized borophene possesses moderate and anisotropic carrier mobility, which is comparable to or even higher than some 2D materials such as MoS2 and phosphorene. Our work provides a feasible strategy to effectively stabilize the graphene‐like borophene and tune the electronic properties with great potentials for electronic applications. Double‐sized functionalization by monovalent functional groups (F, Cl, Br, I, OH, and NH2) is predicted to be an effective and feasible way to stabilize the graphene‐like borophene and modulate the electronic properties. The functionalized borophenes are semiconductors with a wide range of gaps, which can be further tuned by external strains, thus are promising for various nanoelectronics applications. [ABSTRACT FROM AUTHOR]

To achieve efficient ammonia synthesis via electrochemical nitrogen reduction reaction (NRR), a qualified catalyst should have both high specific activity and large active surface area. However, integrating these two merits into one single material remains a big challenge due to the difficulty in balancing multiple reaction intermediates. Here, it is demonstrated that the boron‐analogues of MXenes, namely "MBenes", could cope with the challenge and achieve the high activity and large reaction region simultaneously toward NRR. Using extensive density functional theory computations and taking 16 MBenes as representatives, it is identified that seven MBenes (CrB, MoB, WB, Mo2B, V3B4, CrMnB2, and CrFeB2) not only have intrinsic basal plane activity for NRR with limiting potentials ranging from −0.22 to −0.82 V, but also possess superior capability of suppressing the competitive hydrogen evolution reaction. Particularly, different from the MXenes whose surface oxidation may block the active sites, once oxidized, these MBenes can catalyze NRR via the self‐activating process, reducing O*/OH* into H2O* under reaction conditions, and favoring the N2 electroreduction. As a result, the exceptional activity and selectivity, high active area (≈1019 m−2), and antioxidation nature render these MBenes as pH‐universal catalysts for NH3 production without introducing any dopants and defects. [ABSTRACT FROM AUTHOR]

Aqueous zinc ion batteries (ZIBs) are emerging as a highly promising alternative technology for grid-scale applications where high safety, environmental-friendliness, and high specific capacities are needed. It remains a significant challenge, however, to develop a cathode with a high rate capability and long-term cycling stability. Here, we demonstrate diffusion-controlled behavior in the intercalation of zinc ions into highly porous, Mn4+-rich, and low-band-gap NixMn3−xO4 nano-particles with a carbon matrix formed in situ (with the composite denoted as NixMn3−xO4@C, x = 1), which exhibits superior rate capability (139.7 and 98.5 mA h g−1 at 50 and 1200 mA g−1, respectively) and outstanding cycling stability (128.8 mA h g−1 remaining at 400 mA g−1 after 850 cycles). Based on the obtained experimental results and density functional theory (DFT) calculations, cation-site Ni substitution combined with a sufficient doping concentration can decrease the band gap and effectively improve the electronic conductivity in the crystal. Furthermore, the amorphous carbon shell and highly porous Mn4+-rich structure lead to fast electron transport and short Zn2+ diffusion paths in a mild aqueous electrolyte. This study provides an example of a technique to optimize cathode materials for high-performance rechargeable ZIBs and design advanced intercalation-type materials for other energy storage devices. [ABSTRACT FROM AUTHOR]