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Electrochemical reduction of carbon dioxide (CO2) toward chemical and fuel production is a compelling component of the new energy system. Two‐dimensional bismuth with a particular surface has been identified as a highly efficient electrocatalyst for converting CO2 to formate. However, the development of a controllable synthetic strategy for possible large‐scale production of such Bi materials remains highly challenging. Herein, a scalable chemical interface confinement reduction method is proposed for topotactic transformation of BiOBr (001) nanosheets to metallic Bi (001) porous nanosheets (PNS). As expected, the Bi (001) PNS exhibits excellent electrochemical performance on CO2 reduction to formate, with Faradaic efficiency of 95.2% and formate partial current density of 72 mA cm−2. Density functional theory calculations suggest that Bi PNS selectively exposes (001) surfaces with small‐angle grain boundaries can significantly lower the free energy barrier for the formation of *OCHO, which are responsible for the high activity and selectivity toward CO2‐to‐formate conversion. [ABSTRACT FROM AUTHOR]

• The conductivity of the NDWs is three orders of magnitude higher than the T-T DWs but is one order of magnitude lower than the H-H DWs in a LiNbO 3 transistor. • The wall current is affected by discontinuous domain retraction across different voltage sweeping ranges. • The wall current is thermally activated and the activation energy changes at 260 K. Conducting domain walls in an insulating ferroelectric matrix are interesting for the development of next generation multifunctional nanodevices with large output powers. However, electrical conductions are diversified among head-to-head (H-H), neutral (N), and tail-to-tail (T-T) domain walls (DWs) with disputable conduction mechanisms. It is generally accepted that the charged DWs are more electrically conductive than the neutral DWs. However, the charged walls are unstable due to high depolarization energies. Here, we stabilized the H-H DWs, NDWs and T-T DWs within a LiNbO 3 transistor by controlling charge injection in compensation of the domain boundary charge under applied drain–gate, drain–source and gate–source voltages. The walls were created through the local 180° domain reversals in different inclined angles, and the transistors in different sizes were fabricated at the surfaces of 5 mol.% MgO-doped LiNbO 3 single crystals in monodomain patterns. The NDWs are positively charged due to small inclination angles (~1°) and local sideways meandering behavior of the charged dipoles with electrical conduction that is three orders of magnitude higher than that across the T-T DWs but is one order of magnitude lower than that across the H-H DWs. Voltage dependences of wall currents can be fitted according to the space-charge-limited current equation with an exponential coefficient varying between 2.1 and 3.7 in some specific voltage ranges, implying discontinuous domain retraction in different inclined wall angles against the reduced applied voltage to affect the wall current. This finding provides the fundamental physics to improve domain wall conduction via domain reconstruction and broadens the domain wall application in future nano-devices. [ABSTRACT FROM AUTHOR]