Metal-free bifunctional carbon electrocatalysts derived from zeolitic imidazolate frameworks for efficient water splitting

Abstract

Cathodic polarization treatment modulates the surface functional group composition of ZIF-8 derived metal-free carbon catalysts, resulting in enhanced OER/HER activity.

Carbon-Based Metal-Free Electrocatalysis for Energy Conversion, Energy Storage, and Environmental Protection

“…8d), and demonstrated high performances for water splitting with a current density of 10 mA cm −2 over 8 h under a potential of 1.82 V and a faraday efficiency (FE) of 98.0-99.1% in 0.1 M KOH electrolyte [187]. N,P,O-tri-doped porous graphite carbon@ oxidized carbon cloth (donated as: PGC/OCC) has also been developed for overall water splitting with a low overpotential of 410 mV, a current density of 10 mA cm −2 , a small Tafel slope of 83 mV dec −1 , and a long-term electrochemical durability [158].…”

Noble metal-free two dimensional carbon-based electrocatalysts for water splitting

“…The heteroatoms of B, S, N, P, F, and O hold great potential to alter the intrinsic properties of graphene based materials and enable them to adsorb reactant species on their surface without disturbing their electrical conductivities, which shows the availability of foundation for unusual catalytic performances [65][66][67][68]. Furthermore, it has (4) [118] CoO/NC Pyrolysis 1.0 M KOH 1.55 [151] CoP/NC Annealing 1.0 M KOH 1.73 [147] CoP/rGO Annealing/phosphoration 1.0 M KOH 1.56 [138] CoP/rGO Pyrolysis 1.0 M KOH 0.47 [145] Co-BNC Carbonization 1.0 M KOH 1.68 [180] CoP/NPMG Carbonization 1.0 M KOH 1.60 [149] NiP/C Electrodeposition/phosphoration 1.0 M KOH 1.63 [146] VCN@Fe 4 N/FeOOH Annealing 0.1 M KOH 1.60 [153] NiFe-LDH NS@DG Suspension 1.0 M KOH 1.50 [156] been noted that the modification of graphene via high electronegative heteroatom (e.g., N, F, and O) doping can easily modulate the electronic structures by activating the adjacent carbon atoms in the graphene, leading to increase catalytic sites, which ultimately boosts up the electrochemical activities for water splitting [69]. In addition, the co-doping with higher and lower electronegative heteroatoms can also provide a synergistic effect between heteroatoms with a distinctive electronic structure and consequently enhance the activity of heteroatom-doped graphene-based electrocatalysts [70].…”

“…The edge defects, large surface area, and high N-doping content were attributed to the remarkable electrochemical performances. Subsequently, a N-doped carbon-based electrocatalyst with largest surface area of 1017 m 2 g −1 , was developed by cathodic polarization treatment (CPT) for different time after pyrolysis of different precursors [118]. The N-doped carbon-based electrocatalysts prepared by using CPT for 6 h and 4 h demonstrated impressive HER and OER activities, with the overpotentials of ~ 0.16 and ~ 0.48 V at 10 mA cm −2 , and Tafel slopes of 54.7 and 78.5 mV dec −1 in acidic media, respectively.…”

MOF derived carbon based nanocomposite materials as efficient electrocatalysts for oxygen reduction and oxygen and hydrogen evolution reactions

“…Moreover, investigation of Raman spectra also showed that higher carbonization time inicts higher number of defects and severe structural damage to the graphitic carbon matrix, thereby lowering activity. 155 ZIF-67 because of its large cobalt content is an automatic choice for carbonization. Porous Co-P/NC nanopolyhedrons comprising CoP x nanoparticles embedded in N containing C matrix was prepared by the direct carbonization of ZIF-67, followed by phosphidation.…”