Fabrication, photoelectrochemical and electrocatalytic activity of 1D linear Co(II) and Fe(III) TPP-based coordination compounds

Abstract Application of transition metal elements in catalysis has become a research hotspot in recent years. Here, two kinds of transition metal-centered HER electrocatalyst of Co(Ⅱ)TPP-based coordination compounds and Fe(Ⅲ)TPP-based coordination compounds are reported. Both of coordination compounds show high photocurrent response and excellent hydrogen evolution activity. The most attraction is that FeTPP-OA/PVP58, FeTPP-PTA/PVP58, FeTPP-OA/PVP1300 and FeTPP-PTA/PVP1300 possess a special surface with a big spine-like cross which is different to the regular pyramid morphology of the other coordination compounds, and these coordination compounds display superior HER performance compare to the other samples. Especially, FeTPP-OA/PVP58 exhibits a low overpotential of 83 mV at the current density of 10 mA cm−2 and an ultralow Tafel slope of 39 mV dec−1 which is close to the Pt/C (29 mV dec−1). The low charge transfer resistance of 14.4 Ω and high photocurrent of 3 μA under visible light illumination also reveal the outstanding photoelectrochemical property of FeTPP-OA/PVP58. This work provides a novel insight into the design of transition metal-centered HER electrocatalyst with high-efficiency electrocatalytic activity and low cost.