Spin Manipulation and Basal plane activation of 2D Materials for Photoelectrochemical H2 Generation Praveen Kumar* School of Materials Science, Indian Association for the Cultivation of Science, Kolkata-700032, India *Email: praveen.kumar@iacs.res.in Photoelectrochemical splitting of water into hydrogen and oxygen has been accepted as a sustainable way to utilize solar energy. Among several photoactive materials, 2D-Materials connected via van der Waals forces have gained tremendous attention as competent material for PEC HER as the most stable 2H phase (of MoS2) possesses good catalytic property comparable to noble metals, suitable band edge position, appropriate energy bandgap, and photochemical stability. Having all these salient features, 2D materials are still not being utilized to their maximum possibility for PEC HER due to the lack of an alternative way of basal plane activation. Further, growing vertical heterostructures of these 2D-materials on foreign substrates like GaN, Si is also one of the prime concerns to increase the active surface area and promote efficient charge separation & transport. In my talk, I will address some of these issues and also will discuss related successful recent innovations in our laboratory. Moreover, the co-existence of superior catalytic property and strong spin-orbit-coupling (due to structural inversion asymmetry) in two-dimensional polar Janus MoSSe is expected to have spin-dependent catalysis under an external magnetic field. In my presentation, I will demostrte a proof-of-concept of the benign role of an external magnetic field in photoelectrochemical water splitting utilizing both spin and catalytic properties of MoSSe. Photocathodes are fabricated by directly growing a few layers Janus MoSSe on silicon nanowire by solvothermal method. Delaminated Mo2C-Tx MXene is employed to enhance the charge transport. Density functional theory calculations are carried out to comprehend the spin-dependent charge separation mechanism. Due to the synergic effect, the optimized Mo2C-Tx/MoSSe/SiNW photocathode shows a 52% increase in the photocurrent under the 0.4 T magnetic field at zero bias. These findings will offer a fertile ground to cultivate asymmetric two-dimensional material for a wide range of applications. References: 1. Physical Review Materials (2023) 2. Journal of Materials Chemistry A 10 (2022) 19027. 3. Journal of Physical Chemistry Letters 13 (2022) 1334 4. Chemical Engineering Journal 435 (2022) 134963 5. Nano Energy 87 (2021) 106119 6. Renewable & Sustainable Energy Reviews 135 (2021) 110391. 7. ACS Applied Materials & Interfaces 12 (2020) 28792 8. ACS Applied Materials & Interfaces 12 (2020) 37218 9. ACS Applied Energy Materials 3 (2020) 6834 10. Chemical Engineering Journal 397 (2020) 125415. 11. ACS Applied Materials & Interfaces, 12 (2020) 13797.