1703691 (1 of 27)
2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Advanced Biomass-Derived Electrocatalysts for the Oxygen
Maryam Borghei,* Janika Lehtonen, Liang Liu, and Orlando J. Rojas*
and development is obtaining more eco-
nomical electrodes without compromising
the activity and durability. Porous carbon
materials have been investigated intensely
because of their outstanding properties,
including electrical conductivity, stability,
tunable morphology, and functionality.
The emergence of carbon nanotubes
(CNTs) and graphene has markedly inﬂu-
enced the development of the electrodes
of fuel cells. Despite the promising per-
formance of electrodes based on CNT
or graphene, their use on a large scale
is presently limited by the high costs.
Therefore, sustainable and abundant bio-
mass resources have captured attention
as alternative options.
Every year more
than 140 billion metric tons of biomass
are generated globally as waste from agricultural products;
hence, their conversion into novel materials makes sense if
one considers the beneﬁts related to waste reduction. Ligno-
cellulose biomass from plants (phytomass) and animal bio-
mass (zoomass) from livestock farming or human activities are
generated vastly every day, with given ecological impact, GHG
emission, and burdens to waste management.
attention toward conversion of biomass to electrodes for super-
capacitors and batteries has been highlighted recently.
Here, we provide an overview on recent achievements toward
biomass-derived electrocatalysts for the oxygen reduction reac-
tion (ORR), which is a timely topic (Figure 1a). The next two
sections provide a brief description of the ORR mechanism and
synthesis protocols of biomass-derived carbon nanomaterials.
Sections 4–6 describe in detail the strategies for the synthesis,
as well as physicochemical and ORR properties, of catalysts
derived from phyto- and zoomass. More than 70% of the lit-
erature has reported the use of phytomass for the synthesis
of ORR electrocatalysts, of which carbohydrates and polysac-
charides (such as glucose and cellulose derivatives) hold the
largest contributions (Figure 1b). Noticeably, the last two years
have witnessed major efforts to convert lignocellulosic side
streams and residuals (from soybean, coconut shells, seaweed,
and waste plants) as well as animal wastes (poultry feathers,
horns, livestock bones, blood, human hair, etc.) into electroac-
tive porous carbon nanostructures for the ORR.
2. ORR Mechanism and Electrocatalysts
Electroreduction of oxygen consists of a rather complex mech-
anism involving a multielectron transfer process with several
Recent progress in advanced nanostructures synthesized from biomass
resources for the oxygen reduction reaction (ORR) is reviewed. The ORR plays
a signiﬁcant role in the performance of numerous energy-conversion devices,
including low-temperature hydrogen and alcohol fuel cells, microbial fuel
cells, as well as metal–air batteries. The viability of such fuel cells is strongly
related to the cost of the electrodes, especially the cathodic ORR electro-
catalyst. Hence, inexpensive and abundant plant and animal biomass have
become attractive options to obtain electrocatalysts upon conversion into
active carbon. Bioresource selection and processing criteria are discussed in
light of their inﬂuence on the physicochemical properties of the ORR nano-
structures. The resulting electrocatalytic activity and durability are introduced
and compared to those from conventional Pt/C-based electrocatalysts. These
ORR catalysts are also active for oxygen or hydrogen evolution reactions.
Dr. M. Borghei, J. Lehtonen, Prof. O. J. Rojas
Department of Bioproducts and Biosystems
School of Chemical Engineering
FI-00076 Aalto, Finland
E-mail: maryam.borghei@aalto.ﬁ; orlando.rojas@aalto.ﬁ
Department of Bioengineering
Nanjing Forestry University
Nanjing 210037, China
The ORCID identiﬁcation number(s) for the author(s) of this article
can be found under https://doi.org/10.1002/adma.201703691.
Concerns about climate change have been the focus of interna-
tional initiatives such as the Kyoto Protocol (1997) and the Paris
Agreement (2015) for mitigation of greenhouse gasses (GHG).
They aim at keeping global warming below 2 °C through
carbon offsetting, mainly via increasing the share of renewable
energies, energy efﬁciency, and fuel switching.
the European Union (EU) has set up strategies toward the 2050
low-carbon economy with 80% reduction in GHG, of which the
transport and power sectors contribute the largest potential of
These scenarios have stimulated the develop-
ment of novel energy storage and conversion devices (fuel cells,
batteries, and supercapacitors) of which fuel cells have received
tremendous attention due to their wide range of applications.
They span power devices that include stationary (MW-size),
transport (aerospace and terrestrial), and small-scale portable
One of the major challenges in fuel-cell research
Adv. Mater. 2018, 30, 1703691