XPS investigation of MnO₂ deposits functionalized with graphitic carbon nitride

Composite materials based on MnO₂ deposits functionalized with graphitic carbon nitride (gCN) nanostructures are promising (photo)electrocatalysts for oxygen evolution reaction (OER). Besides the individual properties of the two electrode components, mutual interactions at their interface can also exert a significant influence on functional performances. In this work, MnO₂ deposits are synthesized by plasma enhanced-chemical vapor deposition on Ni foam supports and subsequently decorated with two different forms of carbon nitride via electrophoretic deposition. Structural and morphological analyses revealed the formation of β-MnO₂ 2D structures hierarchically assembled into flowerlike architectures, whose surface appeared decorated by 3D particles built up from gCN nanoflakes. Based on the intimate contact between the two semiconductors, an effective electronic and chemical coupling was established at their interface. In the following, we report on a comparative XPS characterization of a bare MnO₂ electrode material and of two MnO₂-gCN composite systems prepared from different carbon nitride powders. Survey spectra as well as detailed scans for C 1s, N 1s, O 1s, and Mn 2p regions are presented and critically discussed.