The objective of my research is to provide a better understanding of fundamental principles and mechanisms involved in the chemistry and physics of surfaces. This interest stems from a need for understanding the fundamental properties of materials in sufficient detail to be able to improve device performances for a variety of technological applications. This can be addressed by the use of scanning probe microscopies (STM, AFM) yielding high-resolution and real-space information on surface phenomena, supported by theoretical calculations (DFT). Strategies are devised to properly interrogate relevant systems at the atomic scale. For instance, surface nano-engineering is investigated with the aim of delivering concepts that can be used for the development of new devices used in, e.g., heterogeneous catalysis, photo-catalysis, molecular electronics and architectures. Our application of ultra-microscopy aims at going beyond the traditional use (i.e. high-magnification topography) of such instrumentation by achieving the following: (1) local electronic and vibrational spectroscopy (STS and IETS) of single atoms/molecules; (2) atomic and molecular manipulation; (3) fast-acquisition (several tens of images per second) towards resolving dynamics at surfaces; and (4) high-pressure measurements towards meaningful studies at the gas/solid interface (UHV-based).  For more information please see our group website.

Our research encompasses a broad range of activities, listed below, with a common objective: to better understand fundamental principles and mechanisms involved in the chemistry and physics at surfaces for the rational nanoscale design of functional materials. Our interest stems from a wish to explore the fundamental properties of the materials, as well as from a need for understanding their properties in sufficient detail to be able to improve device performances in technological applications. We believe many of such issues can be addressed with scanning probe microscopies (STM, AFM) by providing high-resolution, real-space, and time-resolved images of surface phenomena. Strategies are devised to properly interrogate relevant systems at the atomic scale. For instance, surface nano-engineering is investigated with the aim of delivering concepts that can be used for the development of new devices, in a variety of fields such as heterogeneous catalysis, photo-catalysis, opto-electronics, molecular electronics and architectures.

We aim at going beyond the traditional use of such instrumentation (i.e. high-magnification topography) by achieving the following:

• local electronic and vibrational spectroscopy (STS and IETS) of single atoms or molecules;
• atomic and molecular manipulations;
• fast-acquisition (several tens of images per second) towards resolving dynamics at surfaces;
• high-pressure measurements towards meaningful studies at the gas/solid interface (UHV-based).

The various research activities we are presently working on are listed below:

• graphene;
• molecular electronics;
• surface science approach to heterogeneous catalysis;
• and some cool stuff with great colleagues.

Renald contributes to teaching at both sub-honours and honours classes,

Present teaching activities: CH4717 photon based spectroscopies (10 lectures, 1 tutorial); CH2701 mathematical tools for chemists (10 lectures, 16 workshop hours); CH3721 physical chemistry practical laboratory demonstration (60 contact hours); Convenor for integrating chemistry (CH4461 and CH5461); Convenor for the honours research pojects for MChem and BSC students (CH4442 and CH5441).

Past teaching activities: Quantum mechanics; Physical chemistry; Physics practical laboratory demonstrations; etc.

During my PhD studies at EPFL, I studied the deposition of mass-selected metal clusters on metal surfaces, by investigating the effect of cluster kinetic-energy (soft to energetic impacts) on the morphology and thermal stability of the nano-structures obtained. For that purpose, a complex experimental set-up was developed (home-built), combining 4K-STM and Helium Atom Scattering [Rev.Sci.Instrum. 71, 2818 (2000)]. I was the first to provide direct atomic-scale evidence that soft-landing of mass-selected metal clusters on a metal substrate (i.e. pre-selected identity preserved) is achievable via dissipation of their total kinetic energy by a rare gas buffer layer pre-adsorbed on the substrate [Phys.Rev.Lett. 86, 3590 (2001)].

In the group of Prof. Besenbacher (Aarhus, Denmark), my scientific interests shifted towards physical chemistry. I exploited high-resolution, time-resolved STM to study fundamental surface processes related to catalysis. In particular, I concentrated on the interaction of rutile TiO₂(110) surfaces, and their inherent defects, with metals (Au) and small molecules (H₂O, O₂). In this context, I was the first to report on the experimental confirmation that oxygen vacancies (1) are the active sites for water dissociation [Phys.Rev.Lett. 87, 266104 (2001)], and (2) are the nucleation (trapping centres) for Au nano-clusters [Phys.Rev.Lett. 90, 026101 (2003)]. Furthermore, I discovered a novel adsorbate-assisted diffusion mechanism of OH groups [Science 299, 377 (2003)], and reconciled diverging interpretations on the nature of the Au/TiO₂ interfacial bonding existing between the traditional catalysis chemists and the surface science community [Science 315, 1692 (2007)].

Renald graduated in 1996 from the Dept. of Physics of the University of Lausanne, Switzerland. He then carried out PhD studies at the Dept. of Physics of the Swiss Federal Institute of Technology in Lausanne (EPFL) followed by postdoctoral research at the Interdisciplinary Nanoscience Centre of the University of Aarhus in the group of Professor F. Besenbacher. Since 2006 he has been at the School of Chemistry in St Andrews, firstly as an EaStCHEM Hirst Fellow and then since 2011 as a Lecturer. His expertise lies in the application of high-resolution scanning probe microscopy and spectroscopy (SPM and STS) to study fundamental processes related to the nano-scale design and characterisation of functional materials. His contribution to the field of SPM has been significant, with several publications in highly-regarded scientific journals (Science, Nature Commnications, ACS Nano, Nano Letters, Physical Review Letters).