We develop an N-coordination strategy to design a robust CO reduction reaction (CORR) electrocatalyst with atomically dispersed Co-N site anchored on polymer-derived hollow N-doped porous carbon spheres. Our catalyst exhibits high selectivity for CORR with CO Faradaic efficiency (FE) above 90% over a wide potential range from -0.57 to -0.88 V (the FE exceeded 99% at -0.73 and -0.79 V). The CO current density and FE remained nearly unchanged after electrolyzing 10 h, revealing remarkable stability. Experiments and density functional theory calculations demonstrate single-atom Co-N site is the dominating active center simultaneously for CO activation, the rapid formation of key intermediate COOH* as well as the desorption of CO.

© 2020, The Author(s), under exclusive licence to Springer Nature Limited. The use of nitrogen fertilizers has been estimated to have supported 27% of the world's population over the past century. Urea (CO(NH2)2) is conventionally synthesized through two consecutive industrial processes, N2 + H2 → NH3 followed by NH3 + CO2 → urea. Both reactions operate under harsh conditions and consume more than 2% of the world's energy. Urea synthesis consumes approximately 80% of the NH3 produced globally. Here we directly coupled N2 and CO2 in H2O to produce urea under ambient conditions. The process was carried out using an electrocatalyst consisting of PdCu alloy nanoparticles on TiO2 nanosheets. This coupling reaction occurs through the formation of C-N bonds via the thermodynamically spontaneous reaction between *N=N* and CO. Products were identified and quantified using isotope labelling and the mechanism investigated using isotope-labelled operando synchrotron-radiation Fourier transform infrared spectroscopy. A high rate of urea formation of 3.36 mmol g-1 h-1 and corresponding Faradic efficiency of 8.92% were measured at-0.4 V versus reversible hydrogen electrode.

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We report a general synthetic strategy for highly robust growth of diverse lateral heterostructures, multiheterostructures, and superlattices from two-dimensional (2D) atomic crystals. A reverse flow during the temperature-swing stage in the sequential vapor deposition growth process allowed us to cool the existing 2D crystals to prevent undesired thermal degradation and uncontrolled homogeneous nucleation, thus enabling highly robust block-by-block epitaxial growth. Raman and photoluminescence mapping studies showed that a wide range of 2D heterostructures (such as WS-WSe and WS-MoSe), multiheterostructures (such as WS-WSe-MoS and WS-MoSe-WSe), and superlattices (such as WS-WSe-WS-WSe-WS) were readily prepared with precisely controlled spatial modulation. Transmission electron microscope studies showed clear chemical modulation with atomically sharp interfaces. Electrical transport studies of WSe-WS lateral junctions showed well-defined diode characteristics with a rectification ratio up to 10.

Noble-metal alloys are widely used as heterogeneous catalysts. However, due to the existence of scaling properties of adsorption energies on transition metal surfaces, the enhancement of catalytic activity is frequently accompanied by side reactions leading to a reduction in selectivity for the target product. Herein, we describe an approach to breaking the scaling relationship for propane dehydrogenation, an industrially important reaction, by assembling single atom alloys (SAAs), to achieve simultaneous enhancement of propylene selectivity and propane conversion. We synthesize γ-alumina-supported platinum/copper SAA catalysts by incipient wetness co-impregnation method with a high copper to platinum ratio. Single platinum atoms dispersed on copper nanoparticles dramatically enhance the desorption of surface-bounded propylene and prohibit its further dehydrogenation, resulting in high propylene selectivity (~90%). Unlike previous reported SAA applications at low temperatures (<400 °C), Pt/Cu SAA shows excellent stability of more than 120 h of operation under atmospheric pressure at 520 °C.

Surface-supported isolated atoms in single-atom catalysts (SACs) are usually stabilized by diverse defects. The fabrication of high-metal-loading and thermally stable SACs remains a formidable challenge due to the difficulty of creating high densities of underpinning stable defects. Here we report that isolated Pt atoms can be stabilized through a strong covalent metal-support interaction (CMSI) that is not associated with support defects, yielding a high-loading and thermally stable SAC by trapping either the already deposited Pt atoms or the PtO2 units vaporized from nanoparticles during high-temperature calcination. Experimental and computational modeling studies reveal that iron oxide reducibility is crucial to anchor isolated Pt atoms. The resulting high concentrations of single atoms enable specific activities far exceeding those of conventional nanoparticle catalysts. This non defect-stabilization strategy can be extended to non-reducible supports by simply doping with iron oxide, thus paving a new way for constructing high-loading SACs for diverse industrially important catalytic reactions.

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Ac ompetitive complexation strategy has been developed to construct an ovel electrocatalyst with Zn-Co atomic pairs coordinated on Nd oped carbon support (Zn/ CoN-C). Sucha rchitecture offers enhanced binding ability of O 2 ,s ignificantly elongates the O À Ol ength (from 1.23 to 1.42 ), and thus facilitates the cleavage of O À Ob ond, showing at heoretical overpotential of 0.335 Vd uring ORR process.A saresult, the Zn/CoN-C catalyst exhibits outstanding ORR performance in both alkaline and acid conditions with ah alf-wave potential of 0.861 and 0.796 Vr espectively. The in situ XANES analysis suggests Co as the active center during the ORR. The assembled zinc-air battery with Zn/CoN-Ca sc athode catalyst presents am aximum power density of 230 mW cm À2 along with excellent operation durability.T he excellent catalytic activity in acid is also verified by H 2 /O 2 fuel cell tests (peak power density of 705 mW cm À2 ).