Efficient Oxygen Evolution Reaction on Polyethylene Glycol‐Modified BiVO₄ Photoanode by Speeding up Proton Transfer

Abstract

The rate‐determining step of the oxygen evolution reaction based on a semiconductor photoanode is the formation of the OO bond. Herein, polyethylene glycol (PEG)‐modified BiVO4 photoanodes are reported, in which protons can be transferred quickly due to the high proton conductivity of PEG, resulting in the acceleration of the OO bond formation rate. These are fully demonstrated by different kinetic isotope effect values. Moreover, the open‐circuit voltage (Uoc) further illustrates that PEG passivates the surface states and surface charge recombination is reduced. The composite photoanode can achieve a maximum photocurrent density of 3.64 mA cm−2 at 1.23 V compared to 1.04 mA cm−2 for pure BiVO4, and an onset potential of 170 mV, which is a 230 mV negative shift compared to pure BiVO4. This work provides a new strategy to accelerate water oxidation kinetics for photoanodes by speeding up the transfer of the proton and the OO bond formation rate.

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“…23b that the KIE values of BVO are all higher than 2, indicating that the proton transfer process is the RDS of the water oxidation reaction, corresponding to the O—H bond rupture 17 . The KIE values of PTh/BVO are less than that of BVO, which means that the proton transfer process is well promoted, thus the water oxidation reaction kinetics can be improved more effectively and holes can be fast transferred to the water 57 , 58 . This can be elucidated by the good hydrophilicity of PTh (Supplementary Fig.…”

Polyoxometalates Embedded into Covalent Triazine Frameworks Regulating Charge Transfer for Visible-Light-Driven Synthesis of Functionalized Sulfoxides and Detoxification of Mustard Gas Simulants

“…All samples immediately exhibit a significant photocurrent intensities upon intermittent irradiation with a 300 W Xe lamp (Figure d). Besides, SiW 12 -CTF (4.12 uA/cm 2 ) exhibits the highest photocurrent intensities in compounds 1 – 3 , and reaches 1.5 times higher photocurrent density compared to bare CTF (2.48 uA/cm 2 ). , Subsequently, electrochemical impedance spectroscopy (EIS) tests were employed to value the interfacial resistance and charge transfer efficiency . In general, the smaller the radius of the semicircular Nyquist plot, the lower the interfacial migration resistance.…”

“…39,40 Subsequently, electrochemical impedance spectroscopy (EIS) tests were employed to value the interfacial resistance and charge transfer efficiency. 41 In general, the smaller the radius of the semicircular Nyquist plot, the lower the interfacial migration resistance. As expected, POM-CTFs exhibit smaller arc radius than the pure CTF, especially SiW 12 -CTF with the smallest arc radius, which demonstrates that grafting POMs onto CTF could improve photocatalytic activity (Figure 3e).…”

The Positive Versus Negative Effects of Defect Engineering for Solar Water Splitting: A Review

“…Moreover, this suggested that the attachment of the FeCo-MOF onto the surface of Fe 2 O 3 effectively passivated the surface states and suppressed charge recombination. Deng et al [123] achieved surface passivation of BiVO 4 photoanodes by simply immersing them in a polyethylene glycol (PEG) solution. Open-circuit voltage measurements showed that treated BiVO 4 exhibited a higher potential difference, indicating that the anchored PEG functioned as a passivating agent for surface states, preventing charge recombination.…”