Recent Advances in Green Hydrogen Production by Electrolyzing Water with Anion-Exchange Membrane

Abstract

The development of clean and efficient renewable energy is of great strategic importance to realize green energy conversion and low-carbon growth. Hydrogen energy, as a renewable energy with "zero carbon emission", can be efficiently converted into hydrogen energy and electric energy by electrolysis of water to hydrogen technology. Anion-exchange membrane water electrolysis (AEMWE), substantially advanced by nonprecious metal electrocatalysts, is among the most cost-effective and promising water electrolysis technologies, combining the advantages of proton exchange membranes with the proven technology of traditional alkaline water electrolysis and potentially eliminating the disadvantages of both. In this paper, the latest results of AEMWE research in recent years are summarized, including the AEMWE mechanism study and the hot issues of low-cost transition metal hydrogen evolution reaction and oxygen evolution reaction electrocatalyst design in recent years. The key factors affecting the performance of AEMWE are pointed out, and further challenges and opportunities encountered in large-scale industrialization are discussed. Finally, this review provides strong guidance for advancing AEMWE.

Fig. 1.

Schematic of “green hydrogen” [11].

Fig. 2.

AEM electrolytic hydrogen production basic principles [164].

Fig. 3.

Substrate material diagram for self-supporting electrodes [165].

Fig. 4.

Mechanisms of the OER response [68].

Fig. 5.

Comparative performance of AEMWEs. (A) Polarization curves. (B) Electrochemical impedance spectroscopy (EIS) at 1.7 V. (C) Tafel plots. (D) AEMWE long-term durability recorded at 60 °C, 1.0 A cm⁻² constant current condition [78].

Fig. 6.

AEM electrolyzer performance of NiFe₂O₄ [85].

Fig. 7.

(A) AEMWE cell polarization curves for NiFe-LDH and Pt measured in 1 M KOH. (B) Plot of HFR values versus current density. (C) AEMWE performance: 53 h with an asterisk denotes the point at which the cell temperature became 70 °C; 110 h with an asterisk denotes when the temperature rose to 80 °C again [97].

Fig. 8.

(A) Schematic of the structure of the AEMWE cell. (B) Performance of AEMWE at different temperatures (C) and 80 °C. (D) Performance of AEMWE. (E) Long-term durability of the material at 1 A cm⁻² [100].

Fig. 9.

(A) Diagram of AEMWE device. (B) Polarization curve of NCP-10. (C) Polarization curve. (D) Nyquist plot. (E) Long-term stability testing. (F) Stability test. (G) Scanning electron microscopy (SEM) image. (H) Polarization curves of single cell [105].

Fig. 10.

(A) Schematic diagram of the single-cell structure. (B) Polarization curves of Pt/C||FAA-3-50||NiS₂/Ni₃S₄ cell at 5 mV⁻¹. (C) Polarization curves after conditioning at 1.7 V for 6 h by a galvanostatic method (5 min step⁻¹). (D) Stability at 1,000 mA cm⁻². (E) Polarization curves before and after stability test [112].

Fig. 11.

(A) Schematic of AEMWE. (B) Current-density versus voltage (I–V ) curves of AEMWE cell. (C) Timing test at different current densities. (D) Stability test in the AEMWE electrolyzer [117].

Fig. 12.

(A) Comparison of NiFe LDH performance determinants. (B) Comparison of electrocatalytic performance. (C) Schematic diagram of the electrolysis cell. (D) Polarization curves of overall water splitting measurement and the stability test in AEM cells for 90 h. (E) Stack structure of AEM electrolysis cell for operation [123].

Fig. 13.

Schematic diagram of HER reaction mechanism [125].

Fig. 14.

(A) Schematic diagram of AEMWE. (B) Single-cell AEMWE. Application of Co₃S₄ and Cu_0.81Co_2.19O₄ NS/NF to HER and OER electrodes. (C) Linear sweep voltammetry (LSV) polarization curves. (D) Durability test [146].

Fig. 15.

AEMWE device assembly and performance testing. (A) Schematic of the CCM in the AEMWE device. (B) Scanning electron microscope image of CCM. (C) Photo of the assembled flow cell. (D) Polarization curves of different CCMs (Pt/C//RuO₂, Ni₃N@W₅N₄//NFP, Pt/C//NFP). (E) Stability curve of Ni₃N@W₅N₄//NFP CCM in flow cell at 1 A cm⁻². Insets: Photographs of the main components of the flow cell [147].

Fig. 16.

(A) Schematic of the AEM electrolyzer. (B) EIS diagram. (C) LSV polarization curves measured in NiFe LDH//AEM//TFCNP electrolyzer. (D) AEMWE performance test [148].

Fig. 17.

(A) Schematic of the AEMWE. (B) LSV plots. (C) LSV plots at 20 and 60 °C. (D) EIS plots for 1.0 M KOH. (E) EIS plots. (F) Stability measurements [152].