Robert C Pullar

Robert C Pullar
Università Ca' Foscari Venezia | UNIVE · Department of Molecular Science and Nanosystems

PhD Materials Engineering

About

255
Publications
69,697
Reads
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8,100
Citations
Citations since 2017
109 Research Items
5218 Citations
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201720182019202020212022202302004006008001,000
201720182019202020212022202302004006008001,000
201720182019202020212022202302004006008001,000
Introduction
My paper "Hexagonal ferrites: A review of the synthesis, properties and applications of hexaferrite ceramics" (DOI 10.1016/j.pmatsci.2012.04.001) was the 3rd most cited PMS article in its first 5 years, now with >32000 views. With >1600 citations (Highly Cited Paper on ESI), it is the 9th most cited Portuguese Materials Science paper on Scopus (2nd most cited since 2007), & the most cited hexaferrites publication of the last 50 years. https://doi.org/10.1016/j.pmatsci.2012.04.001
Additional affiliations
November 2020 - present
Università Ca' Foscari Venezia
Position
  • Associate Professor (equivalent to Senior Lecturer)
June 2009 - October 2020
University of Aveiro
Position
  • Prinicipal Investigator
Description
  • Prinicipal Investigator, research position equivalent to Associate Professor. I am now a visiting Professor at Aveiro/CICECO.
November 2008 - May 2009
Foundation for Research and Technology - Hellas
Position
  • Marie Curie Fellowship in Nanosynthesis
Education
September 1996 - June 2000
The University of Warwick
Field of study
  • Materials Engineering
September 1991 - June 1993
Bangor University
Field of study
  • Inorganic Chemistry
October 1987 - June 1991
University of Leicester
Field of study
  • Chemistry

Publications

Publications (255)
Chapter
With increasing demand for renewable energy and fuels there much interest in solar thermochemical fuel production (STFP), the use of concentrated solar power (CSP) to power the splitting of water and carbon dioxide into H2 and CO for sustainable fuels. This is usually a two-step process: the reduction of a catalyst at high temperatures followed by...
Article
The objective of this study is to show the adsorption power of Tunisian smectitic clay from Jebel Aidoudi from the region of El Hamma (southern Tunisia). A cationic dye (Methylene Blue: MB) and an anionic dye (Orange II: OII) are used to determine the maximum absorbability of clay. Physico-chemical characterization tests (XRD, XRF, SBET) on the cla...
Article
Indium substituted X-type Ba2Zn2InxFe28-xO46 (0.0≤x≤2.0) ferrites were synthesised by a citrate-gel aqueous combustion technique, and heated at 1300 °C. XRD, FTIR, SEM with EDX, magnetic hysteresis, Mössbauer spectroscopy, UV–vis spectroscopy, and dielectric measurements up to 20 GHz have been carried out to study the modification of the structural...
Article
The hexagonal Z-type ferrite Sr3Co2Fe24O41 (SrZ) was first synthesised in 2001 and reported as being a room temperature multiferroic material in 2010, with subsequent investigations into its multiferroic properties, but little into high frequency and microwave properties, and ferromagnetic resonance frequency (FMR), which determines its ability as...
Article
Full-text available
This paper presents a study on orange II sodium salt (OII) degradation based on iron nanoparticles supported by kaolinite clays. The effects of nanoscale iron and initial dye concentration, as well as hydrogen peroxide dosage in a Fenton process, on the degradation of OII were studied. These nanoparticles were synthesized by green methods using cof...
Article
Full-text available
A pure TiO2 thin film (100–120 nm) was made from a green aqueous sol–gel precursor on FTO glass and calcined at 430 °C. It was a mix of amorphous, anatase, rutile and brookite TiO2 phases, and exhibited very good electrochromic properties over visible and NIR wavelengths with an applied bias of +0.1 V to −1.5 V. It was highly transparent showing ex...
Article
Download for free for 50 days at: https://authors.elsevier.com/c/1eh8Mvn2L-k8U Ba2Zn2Fe28O46 hexaferrite was prepared using green synthesis with different quantities of ginger root extract (obtained from 0.0, 17.5, 35, 52.5 and 70 g of ginger root) as a natural antioxidant reducing agent. The dried precipitates were preheated at 550 °C/4 h and fina...
Article
Full-text available
The present study concerns the elimination by retention of the anionic dye orange II (OII) from aqueous solutions was studied using a silica gel prepared from Tunisian silica sands (Barremian age). These Sidi Aich sands were collected in central Tunisia. The collected raw silica sand from the Jebel Meloussi (central Tunisia) was characterised by di...
Article
Full-text available
We report the first ever robocast (additive manufacturing/3D printing) sintered ceria scaffolds, and explore their use for the production of renewable fuels via solar thermochemical fuel production (STFP, water and carbon dioxide splitting using concentrated solar energy). CeO2 catalyst scaffolds were fabricated as 50 mm diameter discs (struts and...
Article
Full-text available
Environmentally conscious biomorphic ceramics (Ecoceramics) are a new class of material manufactured from renewable resources and wastes. Sustainable cork wastes were pyrolysed, and this activated carbon template infiltrated with a sol-gel precursor (from aqueous green-chemistry) to form TiO2 on heating in air, with the honeycomb microstructure of...
Article
Full-text available
In this work, alkali-activated fly ash-derived foams were produced at room temperature by direct foaming using aluminum powder. The 1 cm3 foams (cubes) were then evaluated as adsorbents to extract heavy metals from aqueous solutions. The foams’ selectivity towards lead, cadmium, zinc, and copper ions was evaluated in single, binary, and multicompon...
Poster
Effect of Al3+ substitution on Structural and Magnetic properties of U-type hexaferrites, synthesized using citrate gel auto-combustion method
Article
Polycrystalline lead-free (1-x)BaFe12O19–x(K0.5Na0.5)NbO3 magnetoelectric ceramic composites (x = 10, 20 and 30 wt%) were fabricated for the first time, comparing various synthesis techniques, namely solid state reaction, sol-gel, co-precipitation and citrate combustion methods for the synthesis of the ferrite phase. As well as the four synthesis r...
Article
Hydroxyapatite (HA, Ca10(PO4)6(OH)2) is the major mineral component of human bone, but has a wide range of interesting and useful properties, and many applications beyond biomedicine. Here we produce HA-based materials from a naturally templated precursor which can have a variety of tailored microstructures and hierarchical porosities, and we inves...
Chapter
The compounds with the general formula AM 2 O 4 (A = Mg, Zn, Co, Ni, Cu; M = Al, Ga, Fe) are referred to as spinels [1], which belong to the face-centered cubic symmetry group F d 3 mn. Their cubic cell contains a close-packed array of 32 oxygen atoms with cations in the tetrahedral and octahedral interstices. In the normal spinel structure, tetrah...
Article
In this paper, we use Tunisian clay materials as alternative low-cost adsorbents, as well as substrates to immobilise TiO 2 for the decolouration of methylene blue (MB) dye solutions. The collected raw clay from the mine of Tamra was characterised by various techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray f...
Preprint
Full-text available
The study describes the chemical–mineralogical characterization of Barremian sand deposits. These Sidi Aich sands were collected in central Tunisia. The collected raw silica sand from the Jebel Meloussi (central Tunisia) was characterised by different techniques, such as X-ray diffraction (XRD), X-ray fluorescence (XRF) and scanning electron micros...
Article
50 days' free access to this article- https://authors.elsevier.com/a/1c3sJ%7E2-F173U Gallium substituted Z-type Sr3GaxCo2-xFe24O41 (x = 0.0–2.0 in steps of 0.4) hexaferrites were synthesised by the sol-gel auto-combustion process, and sintered at 1150 °C. The structural, morphology, magnetic, Mössbauer, dielectric and microwave absorption propert...
Article
Various quantities of ginger (Zingiber officinale) root extract were used to prepare X-type BariumeZinc hexaferrite with the chemical composition Ba2Zn2Fe28O46. The powders were prepared using a combustion treatment method, being pre-heated at 550 deg C for 4 h with the ginger as a fuel, followed by final heating to 900 deg C for 5 h and natural co...
Article
Nanostructured thin films are widely investigated for application in multifunctional devices thank to their peculiar optoelectronic properties. In this work anatase TiO2 nanoparticles (average diameter 10 nm) synthesized by a green aqueous sol-gel route are exploited to fabricate optically active electrodes for pseudocapacitive-electrochromic devic...
Article
Many modern technologies require permanent magnets with combinations of properties that cannot be met by conventional metallic or ceramic magnets. Ferrite/polymer composite magnets are a type of rare-earth free magnet with a wide range of magnetic and material property combinations. The uncertainty surrounding the supply and pricing of rare-earth e...
Article
FREE TO DOWNLOAD FOR 50 DAYS AT https://authors.elsevier.com/c/1bCo9WFfgiv3K Chitosan is a natural polysaccharide widely used in biomedicine, for instance for wound dressing. Hydroxyapatite is a very bioactive calcium phosphate which, if modified with an appropriate element (iron Fe), can also have UV-absorbing properties. In this work, we report t...
Article
This work reports a simple and safe, but powerful, route to depollute lead-containing aqueous solutions. Inorganic polymer foams (cm-size) were used as bulk-type adsorbents. The influence of the specimens’ porosity and activator molarity on the foams’ physical properties and on their lead extraction ability was studied. Then, the best performing sa...
Article
Titanium dioxide is a compound of great interest, due to its functional properties; one of its most important uses is as a photocatalyst. TiO2 coatings can be deposited using different techniques. Aerosol Assisted Chemical Vapour Deposition (AACVD) is particularly interesting, as high temperature or pressure are not necessary to generate the gaseou...
Article
Solar thermochemical conversion of H2O and captured CO2 is considered for the production of high-value solar fuels and CO2 valorization, using non-stoichiometric oxygen-exchange redox materials. This work aims to compare the thermochemical cycle performance of different ceria structures, including biomimetic cork-templated ceria (CTCe), ceria foam...
Article
Full-text available
OPEN ACCESS - FREE TO DOWNLOAD Bioactive glass scaffolds are used in bone and tissue biomedical implants, and there is great interest in their fabrication by additive manufacturing/3D printing techniques, such as robocasting. Scaffolds need to be macroporous with voids ≥100 um to allow cell growth and vascularization, biocompatible and bioactive, w...
Article
DOWNLOAD FREE FOR 1 MONTH AT: https://authors.elsevier.com/a/1aMQs3IWkbyahS Gallium substituted Z-type hexagonal ferrites with chemical composition Sr3Co2-xGaxFe24O41 (x = 0.0,0.4, 0.8, 1.2, 1.6, and 2.0) were successfully synthesised in air at 1200 °C for 5 h using the sol-gel auto-combustion technique, in order to investigate the effect of galliu...
Article
Water splitting by solar energy-driven two-step thermochemical cycles is a promising approach for large-scale production of renewable fuels (e.g. hydrogen). The key challenge is developing materials capable of withstanding the harsh environmental conditions and to ensure high reliability in use, particularly in terms of redox kinetics and better ac...
Article
DOWNLOAD FREE FOR 1 MONTH AT: https://authors.elsevier.com/c/1aRxwI6yu4ckf Geopolymer foams (highly porous materials) have emerged as one of the most exciting materials over the past few years due to their remarkable properties, low cost and green synthesis protocol, enabling their use in various high added-value applications. Review papers on poro...
Article
DOWNLOAD FREE FOR 50 DAYS AT https://authors.elsevier.com/c/1aWWQ~2-EzKM- . Hexagonal ferrites can be employed in a multitude of applications, the most common hexaferrites are the M ferrites such as BaFe12O19 (barium hexaferrite, BaM). It is known that if Fe3+ is substituted with a combination of Ti4+/Co2+ the coercivity of BaM can be reduced to pr...
Article
Calcium carbonate has many applications in different fields; its use in environment remediation particularly considered, due to its non-toxicity and potentially high efficiency. The structure, morphology and surface features of calcium carbonate can greatly affect its performance. Hierarchical porosity, in particular, can be beneficial for several...
Cover Page
Full-text available
Our image of a “micropear” (a pear-shaped crystal (5 microns high) made of hydroxyapatite (HAp) nanoparticles grown on Si-Ca-Na-P bioglass) has won the National Wiki Science Competition for Portugal, in the microscopy section. https://commons.wikimedia.org/wiki/Commons:Wiki_Science_Competition_2019/Winners/Portugal The full description is: Crysta...
Article
To highlight the effect of salt precursors on the final properties, bioactivity and biocompatibility, five quaternary (Si–Ca–P–Na) glass compositions were successfully prepared through two distinct rapid sol–gel routes; one using acetate salt precursors (A) catalysed by nitric acid, and the other using nitrate salts (N) and citric acid as a catalys...
Article
FREE TO DOWNLOAD FOR 50 DAYS AT: https://authors.elsevier.com/c/1ZkEC3O1E1GMLC In this investigation, and for the first time, pyrolysed sustainable cork was used to produce waste-based geopolymer-cork composites with enhanced electromagnetic interference (EMI) shielding properties. The influence of the pyrolysed cork amount and the geopolymer poro...
Article
FREE TO DOWNLOAD FOR 50 DAYS AT: https://authors.elsevier.com/c/1ZjpY7tGO~9x0l The increased use of fertilisers is a well-known problem; linked to this, there is an always higher demand for phosphorus (P). Because of this, it is crucial to use P from all possible sources and, if necessary, turn it into a soluble form, available for plants/crops. In...
Article
Full-text available
This review explores the advances in the synthesis of ceria materials with specific morphologies or porous macro- and microstructures for the solar-driven production of carbon monoxide (CO) from carbon dioxide (CO2). As the demand for renewable energy and fuels continues to grow, there is a great deal of interest in solar thermochemical fuel produc...
Article
We show the influence of two functional ions (Cu2+ and La3+), incorporated into a quaternary (Si, Ca, Na, P) Sol‐Gel derived bioactive glass system, on its particle size, cytotoxicity and bioactivity. By doping the parent glass with the two ions in singular or combined forms, fifteen doped glasses were prepared by a rapid Sol‐Gel technique. The inf...
Article
Recent economic and environmental concerns have prompted intensive research on the development and optimisation of rare-earth free permanent magnets, in particular of ferrites. M-type barium hexaferrites (BaFe12O19, BaM) are a type of technologically important, low-cost permanent magnet, with high Tc and high resistance to oxidation and corrosion....
Article
Magnetic particles were successfully synthesised by a new and simple one-step auto-ignition method, with octylamine as organic fuel and iron nitrate nonahydrate as an oxidant, both in an aqueous solution. After synthesis and stabilising at 550 °C in reduced atmosphere, the samples consisted of mostly well crystalline magnetite (Fe3O4), with a small...
Article
FREE DOWNLOAD FOR 50 DAYS at: https://authors.elsevier.com/a/1YVEm3IWkbyP~X Magnetic spinel ferrite particles were successfully prepared from only iron (III) nitrate, using clove and cinnamon plant extracts for the first time as eco-fuels for auto–ignition synthesis. Both natural substances were shown to play dual roles in the synthesis of the mag...
Article
FREE DOWNLOAD FOR 50 DAYS at: https://authors.elsevier.com/c/1Ydn43QCo9UqBU Green liquor dregs are the most challenging waste stream coming from the pulp and paper industry. Despite tremendous efforts, there are not currently any viable recycling alternatives for this massively produced waste (2 Mt/year), which inevitably ends up in landfills. Urge...
Article
FREE DOWNLOAD FOR 50 DAYS AT: https://authors.elsevier.com/c/1YZ-u7tGO~9vto For the first time, highly porous ZnO-based biomorphic materials were synthesised using cork as a natural sustainable template. In the first step, waste cork powder was pyrolysed and converted into inorganic carbon. This template was then infiltrated using a novel approach...
Article
Bioactive glass powders synthesised by sol‐gel are usually porous and exhibit high specific surface areas, conferring them poor ability for scaffolds fabrication using colloidal processing approaches. The difficulties assocciated with colloidal processing of sol–gel glass have hindered so far the processing of 3–D scaffolds by robocasting. This res...
Article
FREE DOWNLOAD FOR 50 DAYS at: https://authors.elsevier.com/a/1YoVO~2-EzDU7 This paper reports the hierarchical influence of co-doping copper and lanthanum in a sol–gel derived quaternary (Si, Ca, Na, P) bioactive glass on its sintering ability. The mutual effects of Cu & La on density, crystallisation and sinterability were investigated using Tagu...
Cover Page
Full-text available
Cover of Materials Today 23, March 2019, showing an SEM image of our geopolymer spheres ( a few mm in diameter) made from valorised / recylced industrial wastes.
Article
FREE DOWNLOAD FOR 50 DAYS AT: https://authors.elsevier.com/a/1YdaM6CFjZC5PW This research details the successful fabrication of scaffolds by robocasting from high silica sol–gel glass doped with Cu2+ or La3+. The parent HSSGG composition within the system SiO2–CaO–Na2O–P2O5 [67% Si – 24% Ca – 5% Na – 4% P (mol%)] was doped with 5 wt.% Cu2+ or La3+...
Article
FREE DOWNLOAD FOR 50 DAYS at: https://authors.elsevier.com/a/1YRYV3PCJl7r8W This article reports the first robocasting of a sol–gel based glass ceramic scaffold. Sol–gel bioactive glass powders usually exhibit high volume fractions of meso– and micro–porosities, bad for colloidal processing as this adsorbs significant portion of the dispersing medi...
Article
FREE DOWNLOAD FOR 50 DAYS at: https://authors.elsevier.com/c/1YRYU3PCJl7rDJ Cork templates were used to produce lightweight bulk biomimetic ecoceramic (environmentally conscious ceramic) monoliths. Bulk/monolithic ceramics are vital for many applications, i.e. energy materials and fuel cells. Using simple and flexible, aqueous green-chemistry proce...
Article
FREE DOWNLOAD FOR 50 DAYS at https://authors.elsevier.com/a/1YKca3Q2WYbH-2 In this investigation cork was used as a low density aggregate in the production of ultra-lightweight and low thermal conductivity inorganic polymer (geopolymer) composites. This novel and highly sustainable material, synthesised at room temperature (23 ºC), may decrease t...
Article
Free download for 50 days at: https://authors.elsevier.com/a/1YEFj~2-EvW7U A quaternary bioactive glass of high silica content was used as a model system for flexible design of powder characteristics obtained by ball milling. The dependence on milling time was used to demonstrate consistency with the expected correlation between comminution and cum...
Cover Page
Full-text available
Cover of The Proceedings of the Royal Society A, Vol 474, Iss 2219, Nov 2018, showing my magnetic strontium hexaferrite (SrFe12O19) ecoceramics, made from sustainable cork templates which maintain the highly porous microstructure of cork.
Article
Full-text available
Because of its electrically conducting properties combined with excellent thermal stability and transparency throughout the visible spectrum, tin oxide (SnO2) is extremely attractive as a transparent conducting material for applications in low-emission window coatings and solar cells, as well as in lithium-ion batteries and gas sensors. It is also...
Presentation
Z-type strontium hexagonal ferrites with chemical composition Sr3Co2-xGaxFe24O41 (where x= 0.0, 0.2, 0.4, 0.8, 1.2, 1.6 and 2.0) were prepared by sol-gel auto combustion method, where a part of Ga ions were replaced by Co ions. The obtain combusted powders were preheated at 550 °C for 4 hrs. followed by 1150 °C for 5 hrs. in a muffle furnace. All p...
Article
In this work, and for the first time, fly ash (FA)-based geopolymer (d = 2.6 mm) spheres were used to extract methylene blue from synthetic wastewaters. The influence of sorption time, dye initial concentration and adsorbent amount on the dye removal efficiency and uptake by the porous spheres was evaluated. The adsorbents’ recyclability and their...
Article
FREE DOWNLOAD FOR 50 DAYS AT: https://authors.elsevier.com/a/1Xtx83IWkbujyv Nanoparticles of zinc-cobalt spinel ferrite Co0.5Zn0.5Fe2O4 (CZFO) were prepared by co-precipitation route, and the effect of the addition of various surfactants (ethanol, PEG, CTAB and acetic acid; surfactant:metals = 0.5:1) on their magnetic and optical properties were in...
Article
In this investigation, an innovative and sustainable solution for glass fibre off-cuts is proposed. For the first time, glass fibre fabrics (non-woven mat) produced during wind turbine blade manufacture were used to produce reinforced inorganic polymer composites. The influence of fabric amount on the composites’ microstructure, water absorption, s...
Article
Outdoor sculptures are part of the sociocultural identity of cities, but are extremely vulnerable to deterioration due to exposure to harsh environmental conditions and climate change. Furthermore, deterioration by micro-organisms renders urgent the need to design protective coatings. This research proposes an integrated methodology for the develop...
Poster
Synthetic dyes, essentially due to their toxic nature, are considered one of the most serious wastewater pollutants and, once deposited in the water lines, become a problem to be removed. 1,2 Adsorption is considered the most effective and simple method for water decontamination. Activated carbons present singular properties, such as their high spe...
Article
This work addresses the solar-driven thermochemical production of CO and O2 from two-step CO2-splitting cycles, using both ceria granules prepared from cork templates (CG) and ceria foams from polyurethane templates (CF). These materials were cycled in a high-temperature indirectly-irradiated solar tubular reactor using a temperature-swing process....
Article
For the first time the feasibility of using an alkaline wastewater coming from the pulp and paper industry as an activator, partially (50 vol.%) replacing commercial sodium hydroxide, in the production of cork-based activated carbons was evaluated. The activated carbons showed the highest value of specific surface area ever reported for cork-based...
Article
In this study, and for the first time, red mud (RM)-based geopolymer spheres were synthesised, with varying porosity and RM content, and then their use as pH regulators was evaluated. The aluminosilicate sources of these inorganic polymers were 100 % waste-based, consisting of a mixture of RM and fly ash wastes. Geopolymer spheres containing up to...