Electropolymerization process dependent poly(1,4-di(2-thienyl)benzene) based full spectrum activated photocathodes for efficient photoelectrochemical hydrogen evolution

Electrochemical surfaces are essential for photoelectrocatalytic processes occuring on semiconductor electrodes, which influence light harvesting capability and charge separation of photoelectrochemical (PEC) hydrogen evolution process. In this work, electrochemical processes through cyclic voltammetry (CV), chronoamperometry (CA) and amperometry (i-t) show different abilities to electropolymerization. It results in poly-1,4-bis(2-thienyl)benzene (PDTB) photoelectordes with various microporous structures and regulated S oxidation states. Benifiting from these effect factors, the light absorption ability and charge separation of PDTB photoelectordes are expanded and promoted. In particular, PDTB photoelectrodes prepared by CA with 1.23 eV band gap and strong light absorption (310-2500 nm) show the best photoelectrochemical activity with a charge transfer resistance of 7 omega, a photocurrent of 0.9 mA cm-2 and increases the onset hydrogen production potential to 0.92 V. The incident photon to current efficiency (IPCE) can reach 14.16 % at 850 nm. It suggests that photoelectrodes from electropolymerization may offer a simple and efficient strategy by adjusting the degree of polymerization to get a promising low band gap semiconductor for efficient PEC water reduction.

Automated summary

Electrochemical processes were used to prepare poly-1,4-bis(2-thienyl)benzene (PDTB) photoelectrodes with various microporous structures and regulated sulfur oxidation states, leading to enhanced light absorption ability and charge separation. Among them, PDTB photoelectrodes prepared by chronoamperometry showed the best photoelectrochemical activity and light absorption capability.