ACS Applied Energy Materials
April 28, 2025
Volume 8, Issue 8
Pages 4838-5501
Hierarchical Hollow Microspheres Assembled from Sulfide-incorporated NiFe-Layered Double Hydroxides for Efficient Electrocatalytic Water Splitting with Low Overpotentials
This study investigates the enhancement of electrocatalysis for overall water splitting through sulfide incorporation into layered double hydroxides (LDHs). Using a one-pot hydrothermal synthesis, hierarchical hollow microspheres of optimized sulfide-doped NiFeโOH (hNiFe-S2) were prepared with thioacetamide as the sulfur precursor. Among the four synthesized LDHs (hCoFeโOH, hNiFeโOH, hCoMgโOH, and hNiMgโOH), hNiFeโOH exhibited the most promising catalytic performance. Accordingly, the sulfide-incorporated derivative hNiFe-S2 demonstrated significantly enhanced bifunctional electrocatalytic activity for both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). For OER, hNiFe-S2 achieved a low overpotential (ฮท) of 235 mV at 10 mA cmโ2, significantly lower than hNiFeโOH (338 mV) and even outperforming commercial Ir/C (336 mV). Notably, hNiFe-S2 also showed improved HER activity, exhibiting ฮท = 175 mV at 50 mA cmโ2, which is significantly lower than that of hNiFeโOH (308 mV). Additionally, hNiFe-S2 demonstrated a Tafel slope of 23 mV decโ1 and excellent stability over 50 h of continuous operation. In a symmetric two-electrode electrolyzer, hNiFe-S2 enabled efficient overall water splitting, achieving a cell voltage of 1.527 V at 10 mA cmโ2 with outstanding long-term durability. Structural analysis revealed that sulfide incorporation improved conductivity, reduced charge-transfer resistance to 1.4 ฮฉ, and increased the electrochemical surface area (Cdl = 28.54 mF cmโ2). These findings demonstrate that hNiFe-S2 is a highly efficient and cost-effective bifunctional catalyst for water splitting, underscoring the importance of structural engineering and compositional tuning in catalyst design for sustainable energy applications.
https://pubs.acs.org/doi/10.1021/acsaem.5c00231
Image created by minjeong Kim / Nanosphere
ACS Applied Energy Materials
April 28, 2025
Volume 8, Issue 8
Pages 4838-5501
Hierarchical Hollow Microspheres Assembled from Sulfide-incorporated NiFe-Layered Double Hydroxides for Efficient Electrocatalytic Water Splitting with Low Overpotentials
This study investigates the enhancement of electrocatalysis for overall water splitting through sulfide incorporation into layered double hydroxides (LDHs). Using a one-pot hydrothermal synthesis, hierarchical hollow microspheres of optimized sulfide-doped NiFeโOH (hNiFe-S2) were prepared with thioacetamide as the sulfur precursor. Among the four synthesized LDHs (hCoFeโOH, hNiFeโOH, hCoMgโOH, and hNiMgโOH), hNiFeโOH exhibited the most promising catalytic performance. Accordingly, the sulfide-incorporated derivative hNiFe-S2 demonstrated significantly enhanced bifunctional electrocatalytic activity for both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). For OER, hNiFe-S2 achieved a low overpotential (ฮท) of 235 mV at 10 mA cmโ2, significantly lower than hNiFeโOH (338 mV) and even outperforming commercial Ir/C (336 mV). Notably, hNiFe-S2 also showed improved HER activity, exhibiting ฮท = 175 mV at 50 mA cmโ2, which is significantly lower than that of hNiFeโOH (308 mV). Additionally, hNiFe-S2 demonstrated a Tafel slope of 23 mV decโ1 and excellent stability over 50 h of continuous operation. In a symmetric two-electrode electrolyzer, hNiFe-S2 enabled efficient overall water splitting, achieving a cell voltage of 1.527 V at 10 mA cmโ2 with outstanding long-term durability. Structural analysis revealed that sulfide incorporation improved conductivity, reduced charge-transfer resistance to 1.4 ฮฉ, and increased the electrochemical surface area (Cdl = 28.54 mF cmโ2). These findings demonstrate that hNiFe-S2 is a highly efficient and cost-effective bifunctional catalyst for water splitting, underscoring the importance of structural engineering and compositional tuning in catalyst design for sustainable energy applications.
https://pubs.acs.org/doi/10.1021/acsaem.5c00231
Image created by minjeong Kim / Nanosphere