Liquid metal forms a thin layer of oxide skin via exposure to oxygen and this layer could be exfoliated by mechanical delamination or gas-injection/solvent-dispersion. Although the room-temperature fabrication of two-dimensional (2D) oxide through gas-injection and water-dispersion has been successfully demonstrated, a synthetic protocol in nonaqueous solvent at elevated temperature still remains as a challenge. Herein we report the mass-production of amorphous 2D SnO x nanoflakes with Bi decoration from liquid Sn–Bi alloy and selected nonaqueous solvents. The functional groups of the solvents play a key role in determining the final morphology of the product and the hydroxyl-rich solvents exhibit the best control toward 2D SnO x . The different solvent-oxide interaction that facilitates this phase-transfer process is further discussed on the basis of DFT calculation. Finally, the as-obtained 2D SnO x is evaluated in electrocatalytic CO2 reduction with high faradaic efficiency (>90%) of formic acid and stable performance over 10 h.

An efficient manner to produce strained atomic structures, is fabricating catalysts with defect-rich atomic structures, including surface defects (such as surface vacancy, doping,) and bulk defects (such as dislocations and grain boundary). [3] Traditional methods to synthesize strain-effected structures, including polyol synthesis, seed-mediated growth, galvanic replacement, electrochemical dealloying, and thermal annealing-induced segregation, [2i,4] are complex and time-consuming processes, which hinder the manufacturing efficiency and limit the wide application of strain-effected catalysts. In addition, strain-induced high-energy surface structures arising from bulk defects, such as dislocations or grain boundary, are more likely to be resistant to surface restructuring during catalysis. [5] It is generally accepted that non-equilibrium conditions tend to induce plentiful defects, so we seek to employ a synthesis method in an extreme environment to realize bulk-defect-strained structures of electrocatalysts. Recently, our group developed a thermal shock nanomanufacturing method which showed enormous potential and achieved great progresses in ultrafast fabrication of nanoparticles, nanowires, graphene, and more. [6] Since the thermal shock process was invented, the method has been widely used in nanomaterials production. [6a-e,7] However, few studies focused on how Designing high-performance and low-cost electrocatalysts is crucial for the electrochemical production of hydrogen. Dislocation-strained IrNi nanoparticles loaded on a carbon nanotube sponge (DSIrNi@CNTS) driven by unsteady thermal shock in an extreme environment are reported here as a highly efficient hydrogen evolution reaction (HER) catalyst. Experimental results demonstrate that numerous dislocations are kinetically trapped in self-assembled IrNi nanoparticles due to the ultrafast quenching and different atomic radii, which can induce strain effects into the IrNi nanoparticles. Such strain-induced highenergy surface structures arising from bulk defects (dislocations), are more likely to be resistant to surface restructuring during catalysis. The catalyst exhibits outstanding HER activity with only 17 mV overpotential to achieve 10 mA cm −2 in an alkaline electrolyte with fabulous stability, exceeding state-of-the-art Pt/C catalysts. These density functional theory results demonstrate that the electronic structure of as-synthesized IrNi nanostructure can be optimized by the strain effects induced by the dislocations, and the free energy of HER can be tuned toward the optimal region. Hydrogen, as a clean energy source with a high energy density, opens up the opportunities of renewable energy and traditional fossil energy, increasing the diversification of energy sources. [1] Nevertheless, the improvement of hydrogen production is limited toward overpotential and stability due to the intrinsically sluggish kinetics of the hydrogen evolution reaction (HER). Strain engineering, which can optimize the electronic structure and chemical activity of the ...

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Development of efficient non-precious catalysts for seawater electrolysis is of great significance but challenging due to the sluggish kinetics of oxygen evolution reaction (OER) and the impairment of chlorine electrochemistry at anode. Herein, we report a heterostructure of Ni 3 S 2 nanoarray with secondary Fe-Ni(OH) 2 lamellar edges that exposes abundant active sites towards seawater oxidation. The resultant Fe-Ni(OH) 2 /Ni 3 S 2 nanoarray works directly as a free-standing anodic electrode in alkaline artificial seawater. It only requires an overpotential of 269 mV to afford a current density of 10 mA•cm −2 and the Tafel slope is as low as 46 mV•dec −1. The 27-hour chronopotentiometry operated at high current density of 100 mA•cm −2 shows negligible deterioration, suggesting good stability of the Fe-Ni(OH) 2 /Ni 3 S 2 @NF electrode. Faraday efficiency for oxygen evolution is up to ~ 95%, revealing decent selectivity of the catalyst in saline water. Such desirable catalytic performance could be benefitted from the introduction of Fe activator and the heterostructure that offers massive active and selective sites. The density functional theory (DFT) calculations indicate that the OER has lower theoretical overpotential than Cl 2 evolution reaction in Fe sites, which is contrary to that of Ni sites. The experimental and theoretical study provides a strong support for the rational design of high-performance Fe-based electrodes for industrial seawater electrolysis.

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