Synthesis of a petroleum asphalt-based nitrogen/sulfur doped porous carbon material and its use as the counter electrode of dye-sensitized solar cells

A nitrogen/sulfur-doped porous carbon material (NSPC) was synthesized using petroleum asphalt as both carbon and sulfur sources, and graphitic carbon nitride (g-C₃N₄) as a template and nitrogen source. Its use as the counter electrode (CE) of dye-sensitized solar cells (DSSCs) was investigated. Results indicated that g-C₃N₄ was totally decomposed during carbonization, giving the NSPC abundant N dopants and nanopores. The NSPC had a high electrocatalytic activity for the reduction of I₃^- without any Pt catalyst and delivered a high power conversion efficiency of 7.91% as the CE of a DSSC, which is slightly superior to that of Pt CE. The NSPC had an ultrahigh pore volume (4.49 cm³/g) and excellent wettability, providing abundant accessible surface area and facilitated the fast mass transport of reactants. NSPC has potential as a low-cost and efficient CE material for the large-scale use of DSSCs, and provides a new way to add value to low-cost petroleum asphalt.