- Energy Materials 20
- Materials Science, general 12
- Nanochemistry 12
- Nanotechnology and Microengineering 12
- Electrochemistry 10
- Nanoscale Science and Technology 10
- Water, general 9
- Biotechnology 8
- Environmental and Sustainability Education 8
- Green Chemistry 8
- Catalysis 7
- Chemistry/Food Science, general 5
- Earth Sciences, general 4
- Engineering, general 4
- Environment, general 4
- Industrial Chemistry/Chemical Engineering 4
- Fossil Fuels (incl. Carbon Capture) 3
- Geology 3
- Industrial and Production Engineering 3
- Energy Systems 2