Hydrogen evolution reaction of one 2D cobalt coordination polymer with coordinated sulfate ion

Abstract

At present, the shortage of energy is becoming more serious. As a new energy source, hydrogen energy is expected to solve the problem of energy shortage. We considered that doping sulfur may lead to better electrocatalytic hydrogen evolution (HER) performance of the coordination polymers. Therefore, we added sulfuric acid to adjust pH and expected to introduce sulfate ions into the structure during the synthesis. Finally, one cobalt-based coordination polymer (CP) was synthesized, namely {[Co4(bibp)4(SO42−)4(H2O)8]}n (1) (bibp ​= ​4,4′-bisimidazolylbiphenyl). As expected, this synergistic effect of cobalt, carbon and sulfur in the structure may enable compound 1 after calcination at high temperature to have better electrocatalytic hydrogen evolution performance. It has a low onset potential and Tafel slope of −137mV and 115 ​mV dec−1, respectively, and an overpotential of −252mV at a current density of 10 ​mA ​cm−2. And we also found that the material also has low resistivity and good stability with a good activity after 8 ​h of cycling.