Boosting 5-Hydroxymethylfurfural Electrooxidation by Porous Biochar via Loading Numerous Surface-Exposed Cobalt Phosphonates.

The electrooxidation of 5-hydroxymethylfurfural (HMF) into 2,5-furandicarboxylic acid (FDCA) demonstrated its unique superiority, not only in reducing overpotential and improving energy conversion efficiency for green hydrogen production but also in utilizing abundant biomass resources and producing high-value-added chemicals. However, designing highly efficient electrocatalysts for HMF electrooxidation (HMF-EOR) with low cost and high performance for large-scale production remained a huge challenge. Herein, we introduced an easy one-step activation process to produce P-doped porous biochar loaded with multiple crystal surfaces exposed to CoP2O6 catalysts (CoP2O6@PC), which exhibited outstanding electrooxidation performance. To achieve a current density of 50 mA cm-2, only a low overpotential of 200 mV was needed for the electrooxidation of HMF in 1.0 M KOH + 10 mM HMF. This performance far surpassed that of other similar materials. CoP2O6@PC exhibited outstanding HMF-EOR performance with high conversion (nearly 100%), selectivity (97.1%), faradaic efficiency (95.3%), and robust stability. This work represents a promising strategy to fabricate macroscale and low-cost HMF-EOR electrocatalysts and achieve potential industrial applications of HMF-EOR.

High-performance electrosorption of lanthanum ion by Mn3O4-loaded phosphorus-doped porous carbon electrodes via capacitive deionization.

Transition-metal-oxide@heteroatom doped porous carbon composites have attracted considerable research interest because of their large theoretical adsorption capacity, excellent electrical conductivity and well-developed pore structure. Herein, Mn3O4-loaded phosphorus-doped porous carbon composites (Mn3O4@PC-900) were designed and fabricated for the electrosorption of La3+ in aqueous solutions. Due to the synergistic effect between Mn3O4 and PC-900, and the active sites provided by Mn-O-Mn, C/PO, C-P-O and Mn-OH, Mn3O4@PC-900 exhibits high electrosorption performance. The electrosorption value of Mn3O4@PC-900 was 45.34% higher than that of PC-900, reaching 93.02 mg g-1. Moreover, the adsorption selectivity reached 87.93% and 89.27% in La3+/Ca2+ and La3+/Na+ coexistence system, respectively. After 15 adsorption-desorption cycles, its adsorption capacity and retention rate were 50.34 mg g-1 and 54.12%, respectively. The electrosorption process is that La3+ first accesses the pores of Mn3O4@PC-900 to generate an electric double layer (EDL), and then undergoes further Faradaic reaction with Mn3O4 and phosphorus-containing functional groups through intercalation, surface adsorption and complexation. This work is hoped to offer a new idea for exploring transition-metal-oxide @ heteroatom doped porous carbon composites for separation and recovery of rare earth elements (REEs) by capacitive deionization.

Preparation of phosphorus-doped porous carbon for high performance supercapacitors by one-step carbonization.

Biomass-derived porous carbon has received increasing attention as an energy storage device due to its cost-effectiveness, ease of manufacture, environmental friendliness, and sustainability. In this work, phosphorus-doped porous carbon was prepared from biomass sawdust (carbon source) and a small amount of phosphoric acid (P-doping source and gas expanding agent) by one-step carbonization. For comparison, parallel studies without phosphate treatment were performed under the same conditions. Benefiting from the addition of phosphoric acid, the prepared carbon material has higher carbon yield, higher specific area and micropore volume. Due to the heteroatom doping of P in the carbon material, the optimized PC-900 sample not only exhibits high specific capacitances of 292 F g-1 and 169.4 F g-1 at current densities of 0.1 A g-1 and 0.5 A g-1, respectively, but also excellent cycle longevity (98.3% capacitance retention after 5000 cycles) in 1 M H2SO4. In addition, the supercapacitor exhibits a high energy density of 10.6 W h kg-1 when the power density is 224.8 W kg-1 at a discharge current density of 0.5 A g-1. This work proposes a sustainable strategy to reuse waste biomass in high-performance and green supercapacitors for advanced energy storage equipment.