 This study proposes a novel approach to improve the efficiency of photocatalytic hydrogen evolution from water using an ultra-thin 2D slash 2D T3C2Tx slash CNN2S4 hetero structure. The 2D slash 2D T3C2Tx slash CNN2S4 hetero structure has been shown to have increased contact area and stronger electronic interactions compared to other structures, resulting in faster charge carrier separation and higher hydrogen evolution rates. This structure also features a sulfur vacancy on the CNN2S4 layer, which acts as an electron trap, further increasing the efficiency of the device. Overall, this study demonstrates how the combination of ultra-thin layers and co-catalysis can be used to create more efficient photocatalytic devices. This article was authored by Tong Ming-su, Chen Jing-men, Lu Yan-chin, and others.