In situ self-grown synthesis of c-MOF@NiO heterostructure anchored to c-MOF/rGA particle electrode: Promoting sustained and efficient degradation of phenol in coking wastewater

Herein, we design a high-performance graphene composite aerogel-based particle electrode with superior phenol degradation effect and long-lasting working capability. In situ anchoring c-MOF@NiO heterostructure on c-MOF/rGA surface was realised with a controlled pyrolysis strategy. The three-dimensional electrocatalytic degradation system composed of c-MOF@NiO/rGA particle electrode achieves 100 % phenol degradation rate in 20 min with a degradation rate constant of 0.1323 min−1, and maintains a phenol degradation rate of 95.27 % after 50 consecutive cycles. Density functional theory calculations show that the c-MOF@NiO heterostructure exhibits the most favorable ΔGOOH*, which effectively promotes the 2e- ORR process and facilitates the generation of H2O2. The defect-induced generation of O2•- and •OH together promotes the mineralisation process of phenol. The particle electrode also exhibits good real coking wastewater treatment capability. This work provides a strong motivation for the deep treatment of coking wastewater and the practical process of 3D electrodes. [Display omitted] •Construction of c-MOF@NiO/rGA by a controlled pyrolysis strategy.•Establishment of a 3D degradation system for efficient electrocatalytic phenol degradation.•c-MOF@NiO/rGA has ultra-long continuous operation capability.•c-MOF@NiO heterostructure induces the generation of H2O2.•O2•- and •OH co-dominate the phenol mineralisation process.