Growth of One-Dimensional RuO₂ Nanowires on g-Carbon Nitride: An Active and Stable Bifunctional Electrocatalyst for Hydrogen and Oxygen Evolution Reactions at All pH Values

Abstract

Development of highly efficient and durable bifunctional electrocatalyst for hydrogen and oxygen evolution reactions (HER and OER) is essential for efficient solar fuel generation. The commercial RuO or RuO-based catalysts are highly active toward OER, but their poor stability under different operating conditions is the main obstacle for their commercialization. Herein, we report growth of one-dimensional highly crystalline RuO nanowires on carbon nitride (1D-RuO-CN) for their applications in HER and OER at all pH values. The 1D-RuO-CN, as an OER catalyst, exhibits a low onset overpotential of ∼200 mV in both acidic and basic media, whereas Tafel slopes are 52 and 56 mV/dec in acidic and basic media, respectively. This catalyst requires a low overpotential of 250 and 260 mV to drive the current density of 10 mA cm in acidic and basic media, respectively. The mass activity of 1D-RuO-CN catalyst is 352 mA mg, which is ∼14 times higher than that of commercial RuO. Most importantly, the 1D-RuO-CN catalyst has remarkably higher stability compared to commercial RuO. This catalyst also exhibits superior HER activity with a current density of 10 mAcm at ∼93 and 95 mV in acidic and basic media. The HER Tafel slopes of this catalyst are 40 mV/dec in acidic condition and 70 mV/dec in basic condition. The HER activity of this catalyst is slightly lower than Pt/C in acidic media, whereas in basic media it is comparable or even better than that of Pt/C at higher overpotentials. The HER stability of this catalyst is also better than that of Pt/C in all pH solutions. This superior catalytic activity of 1D-RuO-CN composite can be attributed to catalyst-support interaction, enhanced mass and electron transport, one-dimensional morphology, and highly crystalline rutile RuO structure.

Vertically Aligned Porous Nickel(II) Hydroxide Nanosheets Supported on Carbon Paper with Long‐Term Oxygen Evolution Performance

“…a) Chronopotentiometric curveso fC P@Ni(OH) 2 (with am ass loadingo f3 .0 mg cm À2 )a nd CP/RuO 2 electrodes measured at 20 and 100 mA cm À2 . [46,47] This transformation would happenm ore prominently at high current densities, whichi s consistentwith our observations. For comparison, curves recorded beforethe chronopotentiometrytest are also given;scan rate:5mV s À1 .c)T afel plots andd)Nyquist plots of CP@Ni(OH) 2 and CP/RuO 2 after1 00 hc hronopotentiometry test;s olid linesare fittingc urves.…”

NiO as a Bifunctional Promoter for RuO2 toward Superior Overall Water Splitting

“…As a result, RuO 2 is believed to be an ideal platform for constructing more advanced bifunctional electrocatalysts for overall water splitting. In this aspect, 1D RuO 2 nanowires on carbon nitride (1D RuO 2 ‐CN x ) and MOF‐derived RuO 2 /Co 3 O 4 heterojunctions have recently been reported as efficient bifunctional electrocatalysts for OER and HER in alkaline environments . Regardless of the enhanced OER/HER activities, these performance‐oriented studies fail to reveal the rational design principle of RuO 2 based bifunctional electrocatalysts.…”

Ultrafine Defective RuO2 Electrocatayst Integrated on Carbon Cloth for Robust Water Oxidation in Acidic Media

“…[7] Proton exchange membrane (PEM) electrolyzers, which operate in acidic electrolyte, provide a solution to these issues. [16,[24][25][26][27][28] Thus, in order to fulfill the requirements of large-scale application, it is still highly desired to develop novel catalysts with better performance, especially better durability. [8] Significant progresses made during the past decades have pointed out that ruthenium and iridium oxides are benchmarking catalyst at low pH.…”