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The adsorption stability, geometry, and electronic and magnetic properties of H2S adsorbed on pristine, vacancy defected, and transition metal (TM)-doped phosphorene-graphene (PG) heterostructures were calculated using density functional theory. In pristine and vacancy defected PG systems, the interaction between H2S and the heterostructure was weak, and the mechanism was physical adsorption. After TM-doping (Ti, V, Cr, Mn, Co, and Ni), the strong orbital hybridisation between the dopant and H2S significantly enhanced the interaction between H2S and the doped heterostructures, and the physisorption mechanism of H2S changed to chemical adsorption. The adsorption energy and desorption time of H2S molecules on Mn-doped PG heterostructures was suitable, which can be applied as sensors to detect H2S gas. The density of states of Cr- and Mn-doped PG heterostructures exhibited asymmetric electron spin states, indicating the existence of magnetic moments. Thus, introducing defects and TM dopants on PG heterostructures can improve H2S sensitivity, providing a theoretical basis for developing gas detection sensors. [ABSTRACT FROM AUTHOR]

Targeted synthesis of acetic acid (CH3COOH) from CO2 photoreduction under mild conditions mainly limits by the kinetic challenge of the C−C coupling. Herein, we utilized doping engineering to build charge‐asymmetrical metal pair sites for boosted C−C coupling, enhancing the activity and selectivity of CO2 photoreduction towards CH3COOH. As a prototype, the Pd doped Co3O4 atomic layers are synthesized, where the established charge‐asymmetrical cobalt pair sites are verified by X‐ray photoelectron spectroscopy and X‐ray absorption near edge spectroscopy spectra. Theoretical calculations not only reveal the charge‐asymmetrical cobalt pair sites caused by Pd atom doping, but also manifest the promoted C−C coupling of double *COOH intermediates through shortening of the coupled C−C bond distance from 1.54 to 1.52 Å and lowering their formation energy barrier from 0.77 to 0.33 eV. Importantly, the decreased reaction energy barrier from the protonation of two*COOH into *CO intermediates for the Pd‐Co3O4 atomic layer slab is 0.49 eV, higher than that of the Co3O4 atomic layer slab (0.41 eV). Therefore, the Pd‐Co3O4 atomic layers exhibit the CH3COOH evolution rate of ca. 13.8 μmol g−1 h−1 with near 100% selectivity, both of which outperform all previously reported single photocatalysts for CO2 photoreduction towards CH3COOH under similar conditions. [ABSTRACT FROM AUTHOR]

Targeted synthesis of acetic acid (CH3COOH) from CO2 photoreduction under mild conditions mainly limits by the kinetic challenge of the C−C coupling. Herein, we utilized doping engineering to build charge‐asymmetrical metal pair sites for boosted C−C coupling, enhancing the activity and selectivity of CO2 photoreduction towards CH3COOH. As a prototype, the Pd doped Co3O4 atomic layers are synthesized, where the established charge‐asymmetrical cobalt pair sites are verified by X‐ray photoelectron spectroscopy and X‐ray absorption near edge spectroscopy spectra. Theoretical calculations not only reveal the charge‐asymmetrical cobalt pair sites caused by Pd atom doping, but also manifest the promoted C−C coupling of double *COOH intermediates through shortening of the coupled C−C bond distance from 1.54 to 1.52 Å and lowering their formation energy barrier from 0.77 to 0.33 eV. Importantly, the decreased reaction energy barrier from the protonation of two*COOH into *CO intermediates for the Pd‐Co3O4 atomic layer slab is 0.49 eV, higher than that of the Co3O4 atomic layer slab (0.41 eV). Therefore, the Pd‐Co3O4 atomic layers exhibit the CH3COOH evolution rate of ca. 13.8 μmol g−1 h−1 with near 100% selectivity, both of which outperform all previously reported single photocatalysts for CO2 photoreduction towards CH3COOH under similar conditions. [ABSTRACT FROM AUTHOR]

Photocatalytic CH4 coupling into high-valued C2H6 is highly attractive, whereas the photosynthetic rate, especially under oxygen-free system, is still unsatisfying. Here, we designed the negatively charged metal supported on metal oxide nanosheets to activate the inert C–H bond in CH4 and hence accelerate CH4 coupling performance. As an example, the synthetic Au/ZnO porous nanosheets exhibit the C2H6 photosynthetic rate of 1,121.6 µmol gcat−1 h−1 and the CH4 conversion rate of 2,374.6 µmol gcat−1 h−1 under oxygen-free system, 2 orders of magnitude higher than those of previously reported photocatalysts. By virtue of several in situ spectroscopic techniques, it is established that the generated Auδ− and O− species together polarized the C–H bond, while the Auδ− and O− species jointly stabilized the CH3 intermediates, which favored the coupling of CH3 intermediate to photosynthesize C2H6 instead of overoxidation into COx. Thus, the design of dual active species is beneficial for achieving high-efficient CH4-to-C2H6 photoconversion. [ABSTRACT FROM AUTHOR]