title: Growth of One-Dimensional RuO2Nanowires 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 RuO2or RuO2-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 RuO2nanowires on carbon nitride (1D-RuO2-CNx) for their applications in HER and OER at all pH values. The 1D-RuO2-CNx, 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-2in acidic and basic media, respectively. The mass activity of 1D-RuO2-CNxcatalyst is 352 mA mg-1, which is ∼14 times higher than that of commercial RuO2. Most importantly, the 1D-RuO2-CNxcatalyst has remarkably higher stability compared to commercial RuO2. This catalyst also exhibits superior HER activity with a current density of 10 mAcm-2at ∼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-RuO2-CNxcomposite can be attributed to catalyst-support interaction, enhanced mass and electron transport, one-dimensional morphology, and highly crystalline rutile RuO2structure.
authors.affiliation: School of Chemical Science, National Institute of Science Education and Research, HBNI , Bhubaneswar 751005, India.
authors.forename: Tanmay
authors.initials: T
authors.lastname: Bhowmik
authors.affiliation: School of Chemical Science, National Institute of Science Education and Research, HBNI , Bhubaneswar 751005, India.
authors.forename: Manas Kumar
authors.initials: MK
authors.lastname: Kundu
authors.affiliation: School of Chemical Science, National Institute of Science Education and Research, HBNI , Bhubaneswar 751005, India.
authors.forename: Sudip
authors.initials: S
authors.lastname: Barman
keywords: bifunctional; graphitic carbon nitride; hydrogen evolution; one-dimensional RuO2 nanowire; oxygen evolution