A quantitative roadmap from catalyst benchmarks to commercial hybrid electrolysis

ChemRxiv

Abstract

Hybrid water electrolysis replaces the sluggish oxygen evolution reaction with the oxidation of an organic substrate, producing hydrogen alongside another value-added chemical. In its most efficient form, the electrochemical oxidative dehydrogenation (EOD) of aldehydes, hydrogen evolves at both electrodes with specific electricity consumption down to 4 kWh kg−1 totalH2 , tenfold lower than conventional water electrolysis. Yet whether such efficiency gains translate into commercial viability has never been tested, as the field lacks standardized performance metrics, limiting catalyst comparability and industrial viability assessment. We propose three performance metrics: Anodic Hydrogen Productivity (AHP), Specific Electricity Consumption (SEC), and Deactivation Rate (DR), and benchmark all reported EOD systems as a case study. A techno-economic analysis links these metrics to net present value and reveals a roadmap to commercial viability: (i) Feedstock selection is the primary economic determinant; (ii) Catalyst stability is the foremost bottleneck, with DRs exceeding tolerable values by three orders of magnitude; (iii) Current density is a linear lever on economics; (iv) Energy efficiency, the property most intensively optimized by the field, matters least, contributing under 1% of net present value for high-value products. This offers quantitative benchmarks for catalyst and process development toward commercially viable EOD. Because the metrics depend only on measurable cell performance, benchmarks and roadmap transfer directly to other hybrid electrolysis concepts.

Authors 7

1. Katharina M. Ebeling Aachen Process Systems Engineering (AVT.SVT)

   RWTH Aachen University · KU Leuven

   Affiliation as printed

   Department of Chemical Engineering

   KU Leuven

   Process Systems Engineering (AVT.SVT), RWTH Aachen University

2. J. Raphael Seidenberg Aachen Process Systems Engineering (AVT.SVT)

   RWTH Aachen University · KU Leuven

   Affiliation as printed

   Department of Chemical Engineering

   KU Leuven

   Process Systems Engineering (AVT.SVT), RWTH Aachen University

3. Binni Zou Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University

4. Dominik Bongartz

   KU Leuven

   Affiliation as printed

   Department of Chemical Engineering

   EnergyVille

   KU Leuven

5. Alexander Mitsos Aachen Process Systems Engineering (AVT.SVT)

   Forschungszentrum Jülich · Jülich Aachen Research Alliance · RWTH Aachen University

   Affiliation as printed

   Energy Systems Engineering (ICE-1, Forschungszentrum Jülich, Jülich, Germany, 52425

   JARA-ENERGY

   Process Systems Engineering (AVT.SVT), RWTH Aachen University

6. Regina Palkovits Aachen

   Forschungszentrum Jülich · Jülich Aachen Research Alliance · RWTH Aachen University

   Affiliation as printed

   Institute for a Sustainable Hydrogen Economy (INW-2, Forschungszentrum Jülich, Jülich, Germany, 52428

   JARA-ENERGY

   RWTH Aachen University

7. Sonja D. Mürtz Aachen

   ETH Zurich · RWTH Aachen University

   Affiliation as printed

   ETH Zurich

   Electrochemical Energy Systems Laboratory, Department of Mechanical and Process Engineering

   RWTH Aachen University