Highly stable all-in-one photoelectrochemical electrodes based on carbon nanowalls

Abstract

Photoelectrochemical (PEC) cells offer a promising approach for developing low-cost solar energy conversion system. However, the lack of stable and cost-effective electrodes remians a bottleneck that hampers their practical applications. Here, we propose a kind of integrated all-in-one three dimensional (3D) carbon nanowall (CNW) electrodes without sensitized semiconductors for stable all-carbon PEC cell. The all-in-one CNW electrodes were fabricated by directly growing CNW on both sides of the SiO2/Si/SiO2 wafer employing Radio Frequency Plasmon Enhance Chemical Vapor Deposition method. Benefited from the interconnected 3D textured structure, CNW can effectively absorb the incident light, and provide a large electrochemical reaction interface at CNW surface that promotes the separation of photo-generated charge carriers, which makes it a superior electrode material. Experimental results show that the all-in-one CNW electrodes possess excellent PEC performance with photocurrent density of 830 μA/cm2. Moreover, the CNW electrodes exhibit excellent photo responses over a wide waveband and superior stability with maintained photocurrent response even after 60 days, which outperforms the electrodes using the other two-dimensional layered materials or semiconductor sensitized electrodes. Such an all-in-one electrode with impressive photovoltaic properties provides a promising platform for PEC applications with high efficiency, eco-friendly, excellent stability and low cost.