Direct Urea/H₂O₂ Fuel Cell with a Hierarchical Porous Nanoglass Anode for High-Efficiency Energy Conversion

Abstract

Direct urea/H 2 O 2 fuel cells (DUFCs) constitute a sustainable bifunctional energy conversion technique devoted to simultaneously eliminating environmental wastewater with urea and generating clean energy. However, exploring an efficient anode material for DUFCs still remains a huge challenge. In this work, a Ni−P hierarchical porous nanoglass (HPNG) catalytic electrode was developed via a low-cost, industrially available electrodeposition technique, which exhibits one of the best performances reported so far in the urea oxidation reaction (UOR), with a potential of 1.330 V at a current density of 10 mA cm −2 and a Tafel slope of 9.77 mV dec −1 . The superior UOR performance of the HPNG electrode is attributed to the excellent intrinsic catalytic activity of NG with a high-energy state and an extremely enlarged surface area from the unique 3D hierarchical porous structure. Furthermore, a DUFC system with the HPNG anode shows a performance breakthrough as indicated by the maximum power density of 38.15 mW cm −2 for 0.5 M urea, representing one of the best yet reported DUFCs. Our work demonstrates the feasibility of the scalable production of HPNG electrodes and is expected to be a great contribution to the development of the practical use of DUFCs in the near future for bifunctional energy conversion.

Advancements in Ni‐based Catalysts for Direct Urea Fuel Cells: A Comprehensive Review

“…Pei et al [95] designed a Ni-P hierarchical porous nanoglass (Ni-P HPNG) using nickel foam as the substrate electrode via a two-step method, including the pulse electrodeposition and dealloying (Figure 7a-d). Then, the catalytic performance of the modified HPNG was compared to another electrode control (Figure 7e).…”

“…Pei et al [95] . designed a Ni‐P hierarchical porous nanoglass (Ni‐P HPNG) using nickel foam as the substrate electrode via a two‐step method, including the pulse electrodeposition and dealloying (Figure 7a–d).…”

Modulation Strategies for the Preparation of High‐Performance Catalysts for Urea Oxidation Reaction and Their Applications

“…Reproduced with permission. [225] Copyright 2023, American Chemical Society. d) The conversion process of urea at Ni 2 P@Ni foam anode.…”

“…The battery test results confirmed that DUFCs could degrade urea in wastewater, and the urea degradation efficiency was ≈50% after 30 min. [225] However, H 2 O 2 at high temperatures easily decomposed into O 2 and water, which is detrimental to fuel utilization. This requires finding an oxidant that is more stable than H 2 O 2 and has a higher theoretical voltage than O 2 .…”

“…c) Schematic design of the DUFC. Reproduced with permission [225]. Copyright 2023, American Chemical Society.…”