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Figure 4: Water electroreduction evaluation. (a) Schematic of the long-range activation in -Ni3S4 heteronanorod. A dot coupled with Ni3S4 nanorod to form the strong interfacial interaction that permits remote electronic structure modulation of Ni3S4, leading to enhanced electrocatalytic properties. (b) Polarization curves for HER of different studied catalysts. Catalyst loading: 1 mg cm−2. Sweep rate: 5 mV s−1. (c) Comparison of η required to yield a current density of 10 mA cm−2 on various Ni-based electrocatalysts. (d) Tafel plots for the different catalysts derived from (b). (e) TOF as a function of η for different catalysts. (f) Plots showing the extraction of the for different catalysts. (g) EIS Nyquist plots of different catalysts. Inset compares Nyquist plots at high-frequency range for -Ni3S4 heteronanorods with different rod lengths. is the real impedance and - is the imaginary impedance. The potential for the Nyquist plot measurement was -0.204 V versus RHE. (h) Schematic of the modulated surface electronic structures of -Ni3S4 heteronanorod, revealing that the interfacial interaction enable the activation of Ni3S4 nanorod up to ~25 nm away from the interface.