Electrochemical conversion of nitrate (NO 3 − ) into ammonia (NH 3 ) recycles nitrogen and offers a route to the production of NH 3 , which is more valuable than dinitrogen gas. However, today's development of NO 3 − electroreduction remains hindered by the lack of a mechanistic picture of how catalyst structure may be tuned to enhance catalytic activity. Here we demonstrate enhanced NO 3 − reduction reaction (NO 3 − RR) performance on Cu 50 Ni 50 alloy catalysts, including a 0.12 V upshift in the half-wave potential and a 6-fold increase in activity compared to those obtained with pure Cu at 0 V vs reversible hydrogen electrode (RHE). Ni alloying enables tuning of the Cu d-band center and modulates the adsorption energies of intermediates such as *NO 3 − , *NO 2 , and *NH 2 . Using density functional theory calculations, we identify a NO 3 − RR-to-NH 3 pathway and offer an adsorption energy−activity relationship for the CuNi alloy system. This correlation between catalyst electronic structure and NO 3 − RR activity offers a design platform for further development of NO 3 − RR catalysts.

Self-healing polymers with microphase-separated structure are plagued with inferior self-healing efficiency at room temperature due to a lack of dynamic interactions in hard domains. Herein, we describe a novel strategy of multiphase active hydrogen bonds (H-bonds), toward realizing fast and efficient self-healing at room temperature, even under harsh conditions. The core conception is to incorporate thiourea moieties into microphase-separated polyurea network to form multistrength H-bonds, which destroy the crystallization of hard domains and, at the same time, insert the dynamic reversible H-bonds in both hard and soft segments, accounting for the surprisingly self-healing performances. The synthesized polymeric material, poly­(dimethylsiloxane)–4,4′-methylenebis­(phenyl isocyanate)–1,1′-thiocarbonyldiimidazole, completely recovers all of the mechanical properties within 4 h at room temperature after rupture. Significantly, self-healing process can also take place at low temperature (restoration with an 85% efficiency in 48 h at −20 °C) or in the water (restoration with a 95% efficiency in 4 h). Depending on the cleavage/reformation of multiphase H-bonds, the material exhibits unprecedented ultrastrechability and notch-insensitiveness. It can be stretched up to 31 500% without fracture and reach a notch-insensitive stretching of up to 18 000%. These exceptional characteristics inspired us to fabricate highly stretchable self-healable underwater conductor and protective self-healing film for suppressing shuttling of polysulfides and preventing crack propagation in S cathode, which provide the pathway for applications in underwater electronic devices or advanced Li–S batteries.

Controlling the crystallization of organic–inorganic hybrid perovskite is of vital importance to achieve high performing perovskite solar cells. The growth mechanism of perovskites has been intensively studied in devices with planar structures and traditional structures. However, for the printable mesoscopic perovskite solar cells, it is difficult to study the crystallization mechanism of perovskite owing to the complicated mesoporous structure. Here, a solvent evaporation controlled crystallization method to achieve ideal crystallization in the mesoscopic structure is provided. Combining results of scanning electron microscope and X‐ray diffraction, it is found that adjusting the evaporation rate of solvent can control the crystallization rate of perovskite and a model for the crystallization process during annealing in mesoporous structures is proposed. Finally, a homogeneous pore filling in the mesoscopic structure without any additives is successfully achieved and a stabilized power conversion efficiency of 16.26% using ternary‐cation perovskite absorber is realized. The findings will provide better understanding of perovskite crystallization in printable mesoscopic perovskite solar cells and pave the way for the commercialization of perovskite solar cells.

Solution-processable organic–inorganic perovskite solar cells have attracted much attention in the past few years. Energy level alignment is of great importance for improving the performance of perovskite solar cells because it strongly influences charge separation and recombination. In this report, we introduce three amide additives, namely, formamide, acetamide, and urea, into the MAPbI3 perovskite by mixing them directly in perovskite precursor solutions. The Fermi level of MAPbI3 shifts from −4.36 eV to −4.63, −4.65, and −4.61 eV, respectively, upon addition of these additives. The charge transfer between perovskite and mp-TiO2 is found to be promoted as determined via TRPL spectra, and recombination in the perovskite is suppressed. As a result, the built-in electric field (V bi) of the printable, hole-conductor-free mesoscopic perovskite solar cells based on these perovskites with amide additives is enhanced and a peak power conversion efficiency of 15.57% is obtained.