1. Synthesis diagram of electrodes (a), SEM images (b-d) and XRD patterns (e-g) of Co precursor/NF (b, e), CoP/NF (c, f), and NiFeOH/CoP/NF-200s (d, g)

S1. TEM characterization of Co precursor/NF, CoP/NF, and NiFeOH/CoP/NF-200s

S2. Cathode LSV curves of CoP/NF, and NiFeOH/CoP/NF-xs prepared with different electrodeposition time (a), and current density difference versus scan rate to calculate the double layer capacities (C_dls) of bare NF, Co precursor/NF, CoP/NF, and NiFeOH/CoP/NF-200s (b)

2. Ni2p(a), Co2p(b), P2p(c), and Fe2p(d) XPS spectra of Co precursor/NF, CoP/NF, and NiFeOH/CoP/NF-200s

3. HER electrocatalytic properties of bare NF, Co precursor/NF, CoP/NF, and NiFeOH/CoP/NF-200s

S3. Anode LSV curves of CoP/NF and NiFeOH/CoP/NF-xs prepared with different electrodeposition time (a), XRD and SEM characterization of NiFeOH/CoP/NF-200s after cathode and anode chronopotentiometry test (b-d)

4. OER electrocatalytic properties of bare NF, Co precursor/NF, CoP/NF, and NiFeOH/CoP/NF-200s

S4. XPS characterization of NiFeOH/CoP/NF-200s before and after HER and OER chronopotentiometry test

5. Electrocatalytic overall water splitting properties of NiFeOH/CoP/NF-200s||NiFeOH/CoP/NF-200s two electrode system and hydrogen production efficiency of the photovoltaic-electrocatalytic system consisting of two electrode cell and GaAs solar cell