Anchored lithium-rich manganese nanoparticles boosting Nd-BiVO4 photoanode for efficient solar-driven water splitting

The recombination rate of electron-hole pairs is much faster than the process of hole capture-electron transfer, which is an important reason for limiting the large-scale application of BiVO4 photoanode. Here, we have pre- pared a new LMNCO-Nd-BiVO4 photoanode using the rare earth element neodymium (Nd) as a dopant and loaded with the lithium-rich manganese material Li1.2Mn0.54Ni0.13Co0.13O2 (LMNCO) as a co-catalyst. The new photoanode exhibited excellent photoelectrochemical (PEC) water oxidation performance and high stability. The photocurrent density reached 2.7 mA cm-2 at 1.23 V vs. reversible hydrogen electrode (RHE), which is 2.8 times than bare BiVO4. A series of characterizations demonstrated that Nd doping increases carrier concentration, reduces impedance. The nickel of LMNCO co-catalyst played the role of hole extraction, while cobalt played the active site. With the synergistic effect of nickel and cobalt, the photogenerated holes can be smoothly transferred to the semiconductor/electrolyte interface and quickly participated in the water oxidation reaction, which significantly improved the photoelectrochemical water oxidation performance and stability of BiVO4 photo- anode. This work is the first time to apply lithium materials to the field of PEC water oxidation, which provides a new idea for the design of BiVO4 photoanode in the future.

Automated summary

In this study, a new LMNCO-Nd-BiVO4 photoanode was prepared using neodymium (Nd) as a dopant and loaded with lithium-rich manganese material Li1.2Mn0.54Ni0.13Co0.13O2 (LMNCO) as a co-catalyst, exhibiting excellent photoelectrochemical (PEC) water oxidation performance and high stability. The photocurrent density reached 2.7 mA cm-2 at 1.23 V vs. reversible hydrogen electrode (RHE), which was 2.8 times higher than bare BiVO4. Nd doping increased carrier concentration and reduced impedance, while the LMNCO co-catalyst played a role in hole extraction and cobalt acted as the active site. The synergistic effect of nickel and cobalt improved the PEC water oxidation performance and stability of BiVO4 photoanode. This study also introduced the application of lithium materials in PEC water oxidation, providing new insights for future design of BiVO4 photoanodes.