Efficient and sustainable synthesis of performant metal/nitrogen-doped
carbon (M–N–C) catalysts for oxygen reduction and evolution
reactions (ORR/OER) is vital for the global switch to green energy
technologies–fuel cells and metal–air batteries. This
study reports a solid-phase template-assisted mechanosynthesis of
Fe–N–C, featuring low-cost and sustainable FeCl3, 2,4,6-tri(2-pyridyl)-1,3,5-triazine (TPTZ), and NaCl. A
NaCl-templated Fe-TPTZ metal–organic material was formed using
facile liquid-assisted grinding/compression. With NaCl, the Fe-TPTZ
template-induced stability allows for a rapid, thus, energy-efficient
pyrolysis. Among the produced materials, 3D-FeNC-LAG exhibits remarkable
performance in ORR (E
1/2 = 0.85 V and E
onset = 1.00 V), OER (E
j=10 = 1.73 V), and in the zinc–air
battery test (power density of 139 mW cm–2). The
multilayer stream mapping (MSM) framework is presented as a tool for
creating a sustainability assessment protocol for the catalyst production
process. MSM employs time, cost, resource, and energy efficiency as
technoeconomic sustainability metrics to assess the potential upstream
impact. MSM analysis shows that the 3D-FeNC-LAG synthesis exhibits
90% overall process efficiency and 97.67% cost efficiency. The proposed
synthetic protocol requires 2 times less processing time and 3 times
less energy without compromising the catalyst efficiency, superior
to the most advanced methods.