The single-layer graphene film, when incorporated with molecular-sized pores, is predicted to be the ultimate membrane. However, the major bottlenecks have been the crack-free transfer of large-area graphene on a porous support, and the incorporation of molecular-sized nanopores. Herein, we report a nanoporous-carbon-assisted transfer technique, yielding a relatively large area (1 mm2), crack-free, suspended graphene film. Gas-sieving (H2/CH4 selectivity up to 25) is observed from the intrinsic defects generated during the chemical-vapor deposition of graphene. Despite the ultralow porosity of 0.025%, an attractive H2 permeance (up to 4.1 × 10−7 mol m−2 s−1 Pa−1) is observed. Finally, we report ozone functionalization-based etching and pore-modification chemistry to etch hydrogen-selective pores, and to shrink the pore-size, improving H2 permeance (up to 300%) and H2/CH4 selectivity (up to 150%). Overall, the scalable transfer, etching, and functionalization methods developed herein are expected to bring nanoporous graphene membranes a step closer to reality.

Earth-abundant electrocatalysts are desirable for the efficient and selective reduction of CO2 to value-added chemicals. Here, a low-cost porous Zn electrocatalyst is synthesized using a facile electrodeposition method to boost the performance of CO2 electrocatalytic reaction (CO2RR). In an H-cell reactor, the porous Zn catalyst can convert CO2 to CO at a remarkably high faradaic efficiency (FE, ∼95%) and current density (27 mA cm–2) at −0.95 V versus the reversible hydrogen electrode. Detailed electrokinetic studies demonstrate that instead of the enhanced intrinsic activity, the dramatically increased active sites play a decisive role in improving the catalytic activity. In addition, the high local pH induced by the highly porous structure of Zn results in enhanced CO selectivity because of the suppressed H2 evolution. Furthermore, we present a straightforward strategy to transform the porous Zn electrode into a gas diffusion electrode. This way, the CO2RR current density can be boosted to 200 mA cm–2 with ∼84% FE for CO at −0.64 V in a flow-cell reactor, which is, to date, the best performance observed over non-noble CO2RR catalysts.

Electrochemical reduction of CO 2 using renewable energy is a promising strategy to mitigate the CO 2 emissions and to produce valuable chemicals. However, the lack of highly selective, highly durable, and nonpreciousmetal catalysts impedes the applications of this reaction. In this work, coppernanowire-supported indium catalysts are proposed as advanced electrocatalysts for the aqueous electroreduction of CO 2 . The catalysts are synthesized by a facile method, which combines In 3+ deposition on Cu(OH) 2 nanowires, mild oxidation, and in situ electroreduction procedures. With a thin layer of metallic In deposited on the surface of the Cu nanowires, the catalyst exhibits a CO Faradaic efficiency of ∼93% at −0.6 to −0.8 V vs RHE; additionally, an unprecedented stability of 60 h is achieved. The characterization results combined with density functional theory (DFT) calculations reveal that the interface of Cu and In plays an essential role in determining the reaction pathway. The calculation results suggest that the Cu−In interface enhances the adsorption strength of *COOH, a key reaction intermediate for CO production, while destabilizes the adsorption of *H, an intermediate for H 2 evolution. We believe that these findings will provide guidance on the rational design of high-performance bimetallic catalysts for CO 2 electroreduction by creating the metal−metal interface structure.

Organic–inorganic metal halide perovskite solar cells (PSCs) have achieved certified power conversion efficiency (PCE) of 25.2% with complex compositional and bandgap engineering. However, the thermal instability of methylammonium (MA) cation can cause the degradation of the perovskite film, remaining a risk for the long‐term stability of the devices. Herein, a unique method is demonstrated to fabricate highly phase‐stable perovskite film without MA by introducing cesium chloride (CsCl) in the double cation (Cs, formamidinium) perovskite precursor. Moreover, due to the suboptimal bandgap of bromide (Br−), the amount of Br− is regulated, leading to high power conversion efficiency. As a result, MA‐free perovskite solar cells achieve remarkable long‐term stability and a PCE of 20.50%, which is one of the best results for MA‐free PSCs. Moreover, the unencapsulated device retains about 80% of the original efficiencies after a 1000 h aging study. These results provide a feasible approach to enhance solar cell stability and performance simultaneously, paving the way for commercializing PSCs.

A highly porous indium electrode was prepared with a facile electrodeposition method, which delivers remarkable activity and selectivity towards electro reduction of Co2.

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