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

Photoelectrochemical (PEC) cells offer a promising approach for developing low-cost solar energy conversion systems. However, the lack of stable and cost-effective electrodes remains a bottleneck that hampers their practical applications. Here, we propose a kind of integrated all-in-one three-dimensional (3D) carbon nanowall (CNW) electrode without sensitized semiconductors for stable all-carbon PEC cells. The all-in-one CNW electrodes were fabricated by directly growing CNW on both sides of the SiO₂/Si/SiO₂ wafer employing the radio frequency plasmon enhanced chemical vapor deposition method. Benefitting from the interconnected 3D textured structure, the CNW can effectively absorb the incident light and provide a large electrochemical reaction interface at the CNW surface that promotes the separation of photogenerated charge carriers, which makes it a superior electrode material. Experimental results show that the all-in-one CNW electrodes possess excellent PEC performance with a photocurrent density of 830 μA cm^-2. Moreover, the CNW electrodes exhibit excellent photoresponses over a wide waveband and superior stability with a maintained photocurrent response, even after 60 d, 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 that is eco-friendly with high efficiency, excellent stability and low cost.