Water electrolysis is an energy-intensive process that benefits from the use of catalysts. Because the canonical hydrogen evolution catalyst is Pt and oxygen evolution catalyst is RuO2, an important research focus for green hydrogen production has been the development of catalysts that rival scarce metals in performance but with reduced or eliminated metal loading. The recent materials research landscape in this area can be visualized in many ways; we begin by presenting the most commonly co-occurring concepts found to be important within each respective study in a clustered network diagram (Figure ). From this high-level conceptual analysis, we see that "Hydrogen evolution reaction" and "Water splitting" concepts have approximately equal primacy in the discussion, while "Oxygen evolution reaction" also frequently co-occurs within documents. This finding underscores that studies of overall water splitting must consider both OER and HER to reach a complete understanding. In addition, "Photocatalysts" are a common research theme from 2011-2021 and have significant overlap with several nanomaterialrelated concepts; the fact that "Electrochemical reaction catalysts" co-occur at approximately the same rate as "Photocatalysts" demonstrates how important photocatalysts have become in the field. Finally, the inclusion of a cluster of surface-oriented concepts such as "Surface structure", "Surface area", and "Pore size" shows the relevance of surface phenomena in catalyst design. Between 2011 and 2021, an over five-fold increase of publication volume is observed in green hydrogen production (Figure ). This is driven by a concomitant increase in both journal articles and patents. After experiencing rapid growth throughout the decade, the publication volume appears to be leveling off.