Valorizing Coffee Waste into N-, P-, O-Heteroatom-Doped Carbons for Metal-Free Electrocatalysis

Spent coffee grounds were valorized as a renewable feedstock to prepare N-, P-, and O-codoped activated carbons via pyrolysis, targeting the development of metal-free electrocatalysts for the oxygen reduction reaction (ORR). Hexachlorocyclotriphosphazene (HCCP) was used as a doping agent, and the influence of different porosity activators such as NH4HCO3, KOH, and oxalic acid was studied. This work employs NH4HCO3 as a benign, metal-free activator and secondary nitrogen source compared against conventional porosity agents. Among the mild activators, NH4HCO3 simultaneously provided nitrogen and released NH3 and CO2, while oxalic acid generated a clean CO2 stream, both contributing to mesoporous structure formation. XPS confirmed the successful incorporation of N and P into the carbon matrix, with a high fraction of graphitic nitrogen enhancing the conductivity and catalytic activity. Raman spectroscopy, TEM, and XRD analyses revealed predominantly sp2-hybridized, turbostratic carbon, with higher structural order at 900 °C compared to 700 °C. The combined effect of pyrolysis temperature, HCCP, and NH4HCO3 produced mesoporous, nitrogen-rich graphitic carbon structures with promising ORR performance, demonstrating a green strategy that maximizes atom economy, minimizes energy input and waste, and transforms low-value biomass into high-performance metal-free electrocatalysts.

Authors

Institutions

Publication Details

Journal
Chemistry of Materials
Published
2026-01-02
DOI
https://doi.org/10.1021/acs.chemmater.5c02518
Primary Topic
Electrocatalysts for Energy Conversion
Type
article
Field-Weighted Citation Impact
0.00
Controls
|||
ALL TIME
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
article

Valorizing Coffee Waste into N-, P-, O-Heteroatom-Doped Carbons for Metal-Free Electrocatalysis

Paolo Sgarbossa, Silvia Nappini, Silvia Carlotto, Antonio Benedetto et al.
Chemistry of Materials
Electrocatalysts for Energy Conversion
article

Valorizing Coffee Waste into N-, P-, O-Heteroatom-Doped Carbons for Metal-Free Electrocatalysis

Paolo Sgarbossa, Silvia Nappini, Silvia Carlotto, Antonio Benedetto, Elisa Moretti, Elena Magnano, Girolamo Casella, Igor Píš, A. Famengo, Anna Scettri, S. Carturan, Francesco Lanero, Federico Zorzi, Tung Tran, Antonio Tricoli, Roberta Bertani, Xuan Minh Chau Ta, Ilargi Napal Azcona, Alissa Di Giulian, Parvez Alam
article en

Abstract

Spent coffee grounds were valorized as a renewable feedstock to prepare N-, P-, and O-codoped activated carbons via pyrolysis, targeting the development of metal-free electrocatalysts for the oxygen reduction reaction (ORR). Hexachlorocyclotriphosphazene (HCCP) was used as a doping agent, and the influence of different porosity activators such as NH4HCO3, KOH, and oxalic acid was studied. This work employs NH4HCO3 as a benign, metal-free activator and secondary nitrogen source compared against conventional porosity agents. Among the mild activators, NH4HCO3 simultaneously provided nitrogen and released NH3 and CO2, while oxalic acid generated a clean CO2 stream, both contributing to mesoporous structure formation. XPS confirmed the successful incorporation of N and P into the carbon matrix, with a high fraction of graphitic nitrogen enhancing the conductivity and catalytic activity. Raman spectroscopy, TEM, and XRD analyses revealed predominantly sp2-hybridized, turbostratic carbon, with higher structural order at 900 °C compared to 700 °C. The combined effect of pyrolysis temperature, HCCP, and NH4HCO3 produced mesoporous, nitrogen-rich graphitic carbon structures with promising ORR performance, demonstrating a green strategy that maximizes atom economy, minimizes energy input and waste, and transforms low-value biomass into high-performance metal-free electrocatalysts.

Chemistry of MaterialsVol. 38(1)
University College Dublin (IE), Roma Tre University (IT), The University of Sydney (AU), University of Padua (IT), Ca' Foscari University of Venice (IT), UniCredit (Italy) (IT), State University of Papua (ID), European Chemical Industry Council (BE), Istituto Officina dei Materiali (IT), Institute of Condensed Matter Chemistry and Technologies for Energy (IT), Consorzio Interuniversitario Reattività Chimica e Catalisi (IT), Universitas Nusa Nipa Maumere (ID), British Society of Soil Science (GB), Conway School of Landscape Design (US), National Institutes of Applied Research (TW)
Openalex Percentile: Top 99%
Electrocatalysts for Energy Conversion
DOISourceOpenAlex
AI Navigator

Ask Laika to Summarize, Analyze, and Connect papers live on the map.

Summarize Papers & Methodologies

Extract key findings, datasets, and comparative methods across publications.

Benchmark Rankings & Visual Analytics

Rank top research institutions, authors, funders, topics, and journals by Field-Weighted Citation Impact (FWCI) and paper volume with instant charts.

Connect Distant Disciplines

Bridge topological clusters on the map to find hidden collaborative intersections.