# Modulation of Electronic Structure in Kraft Lignin‐Derived Mo Single‐Atom Catalysts for Optimized Electrochemical Oxygen Reduction

## TL;DR

This paper presents a sustainable method to create efficient oxygen reduction reaction catalysts using molybdenum single atoms anchored on carbon derived from Kraft lignin.

## Contribution

A scalable and sustainable synthesis of Mo single-atom catalysts from Kraft lignin is introduced, improving oxygen reduction reaction performance.

## Key findings

- Electrochemical measurements show enhanced ORR activity with ≈85% current retention over 50 hours.
- DFT calculations reveal that optimized Mo coordination downshifts the d-band center, improving oxygen intermediate binding.
- Transition from MoC clusters to single-atom sites increases ORR activity.

## Abstract

The sluggish kinetics of the oxygen reduction reaction (ORR) remain a major bottleneck for energy conversion systems such as fuel cells and metal–air batteries. Here, the synthesis of molybdenum single‐atom catalysts (Mo SACs) derived from abundant and low‐cost Kraft lignin is reported. By tuning nitrogen incorporation during carbonization, agglomerated Mo carbide clusters are progressively converted into atomically dispersed Mo active centers anchored on N‐doped carbon. Extensive spectroscopic analyses confirm this structural evolution, while density functional theory calculations reveal that the optimized Mo coordination environment downshifts the d‐band center, enabling the balanced adsorption of oxygen intermediates and thereby improving the intrinsic ORR activity. Electrochemical measurements demonstrate enhanced half‐wave potential, near‐four‐electron transfer pathway, superior selectivity, and excellent durability, with ≈85% current retention over 50 h. Beyond performance, the use of minimally processed Kraft lignin underscores both the economic and environmental advantages of this approach, offering a scalable and sustainable pathway to practical ORR electrocatalysts.

Biomass‐derived lignin is used as a sustainable precursor to synthesize Mo single atoms anchored on a nitrogen‐coordinated carbon framework. As the Mo structure transitions from MoC clusters to isolated single‐atom sites, oxygen evolution reaction (ORR) activity progressively improves. Density functional theory calculations reveal a corresponding downshift of the Mo d‐band center, optimizing oxygen intermediate binding and enhancing ORR kinetics.