Photoelectrochemical (PEC) water splitting is a promising route for synthesizing hydrogen using solar energy without direct CO2 emissions.[1] Recent performance modelling studies have shown that systems consisting of two semiconducting electrodes can achieve higher efficiencies than single absorber configurations.[2] Copper gallium diselenide (CGSe) is a promising wide band gap absorber material for application in a tandem PEC device due to its near-ideal band gap, relatively low cost, and good minority carrier transport.[3] Recent studies involving CGSe as a wide band gap photocathode and platinum as a co-catalyst have shown promising activity but limited stability in alkaline electrolyte.[4] However, many opportunities remain to improve the stability and scalability of these electrodes by improving corrosion resistance and incorporating earth abundant catalysts. Recently, excellent electrochemically stable and earth abundant catalysts, molybdenum disulfide and cobalt phosphide, have emerged as viable alternatives to platinum for catalyzing the hydrogen evolution reaction.[5] [6] In this work, we discuss our progress in synthesizing transition metal sulfide and phosphide films that provide corrosion resistance and catalyze the hydrogen evolution reaction for a variety of PEC water splitting electrodes including CGSe and silicon. First, we explore the challenges inherent to protecting different classes of semiconductor materials including topological and processing constraints. These challenges are overcome by using atomic layer deposition combined with low temperature sulfidation and phosphidation as an effective route to synthesizing stable, low light absorbing, broadly applicable thin film catalysts for use in PEC water splitting. Next, we discuss techniques for bridging the gap in hydrogen evolution activity between precious and non-precious metal catalysts. Finally, we suggest general strategies for maximizing device performance of non-precious metal catalyzed solar water splitting electrodes. [1] M. G. Walter, E. L. Warren, J. R. McKone, S. W. Boettcher, Q. X. Mi, E. A. Santori, N. S. Lewis, Chem. Rev. 2010, 110, 6446. [2] L. C. Seitz, Z. Chen, A. J. Forman, B. A. Pinaud, J. D. Benck, T. F. Jaramillo, ChemSusChem 2014, 7, 1372. [3] B. Marsen, B. Cole, E. L. Miller, Solar Energy Materials and Solar Cells 2008, 92, 1054. [4] M. Moriya, T. Minegishi, H. Kumagai, M. Katayama, J. Kubota, K. Domen, Journal of the American Chemical Society 2013, 135, 3733. [5] T. R. Hellstern, J. D. Benck, J. Kibsgaard, C. Hahn, T. F. Jaramillo, Adv. Energy Mater. 2016, 6. [6] J. D. Benck, S. C. Lee, K. D. Fong, J. Kibsgaard, R. Sinclair, T. F. Jaramillo, Advanced Energy Materials 2014, 4.