Controllable Anchoring of Graphitic Carbon Nitride on MnO<sub>2</sub> Nanoarchitectures for Oxygen Evolution Electrocatalysis
Mattia Benedet, Andrea Gallo, Chiara Maccato, Gian Andrea Rizzi, Davide Barreca, Oleg I. Lebedev, Evgeny Modin, Ruairi McGlynn, Davide Mariotti, Alberto Gasparotto
Abstract
High Resolution Image Download MS PowerPoint Slide The design and fabrication of eco-friendly and cost-effective (photo)electrocatalysts for the oxygen evolution reaction (OER) is a key research goal for a proper management of water splitting to address the global energy crisis. In this work, we focus on the preparation of supported MnO 2 /graphitic carbon nitride (g-CN) OER (photo)electrocatalysts by means of a novel preparation strategy. The proposed route consists of the plasma enhanced-chemical vapor deposition (PE-CVD) of MnO 2 nanoarchitectures on porous Ni scaffolds, the anchoring of controllable g-CN amounts by an amenable electrophoretic deposition (EPD) process, and the ultimate thermal treatment in air. The inherent method versatility and flexibility afforded defective MnO 2 /g-CN nanoarchitectures, featuring a g-CN content and nano-organization tunable as a function of EPD duration and the used carbon nitride precursor. Such a modulation had a direct influence on OER functional performances, which, for the best composite system, corresponded to an overpotential of 430 mV at 10 mA/cm 2, a Tafel slope of ≈70 mV/dec, and a turnover frequency of 6.52 × 10 –3 s –1, accompanied by a very good time stability. The present outcomes, comparing favorably with previous results on analogous systems, were rationalized on the basis of the formation of type-II MnO 2 /g-CN heterojunctions, and yield valuable insights into this class of green (photo)electrocatalysts for end uses in solar-to-fuel conversion and water treatment.