Thermal-Stabilized Protonated TiO2 for Heat-Accelerated Photoelectrochemical Water Splitting.

Enhancing the charge separation efficiency is a big challenge that limits the energy conversion efficiency of photoelectrochemical (PEC) water splitting. Surface states generated by protonation of TiO2 are the efficient charge separation passageways to massively accept or transfer the photogenerated electrons. However, a challenge is to avoid the deprotonation of a protonated TiO2 photoelectrode at the operation temperature. Here, we found that the terminal hydroxyl group (OHT) as surface states on the TiO2 surface generated via electrochemical protonation of TiO2 at 90 °C [90-TiO2-x-(OH)x] is thermally stable. As a result, the thermally enhanced photocurrent of the 90-TiO2-x-(OH)x electrode reached 1.05 mA cm-2 under 80 °C, and the stability was maintained up to 10 h with a slight photocurrent decrease of 3%. The thermally stable surface states as charge separation paths provide an effective method to couple the heat field with the PEC process via thermal-stimulating hopping of polarons.

Designing for a Healthier Makassar, Indonesia: Participatory Systems Mapping.

In Makassar, Indonesia, the USAID-funded Building Healthy Cities (BHC) project engaged 240 multi-sector stakeholders to gather qualitative data across three workshops and two citizen town halls from 2019 to 2021. These data were synthesized with results from BHC's nine other Makassar activities to build maps of the current system and identify high-impact areas for engagement. Contextual findings showed that Makassar leadership has actively innovated and used new technology to improve the city, resulting in improved connectivity and responsiveness. However, this drive toward innovation has strained existing infrastructure and workforce capacity. When this strain fails to meet promised results, citizens are less likely to engage and support the innovations. This is central to the systems map that BHC developed, and is expanded upon through additional patterns that fall within four main areas: (1) leadership, governance, and financing; (2) infrastructure and workforce; (3) collaboration and data; and (4) community cohesion and awareness. Stakeholders found three key leverage points within this context that, if included in every action, could help overcome barriers. These leverage opportunities are: (1) increasing data-driven decision-making; (2) ensuring equitable policy and leadership; and (3) increasing community participation. By combining key patterns discovered in the Context Map with the leverage opportunities, BHC was able to co-create with stakeholders six "coherent actions" that can move Makassar to a healthier, "Sombere (kind-hearted and hospitable) and Smart City." BHC has been working with the city planning office to incorporate the map findings into its bottom-up planning processes and the 5-year mid-term plan for Makassar.