Natalie Johnson

Synthesis of thin film AuPd alloys and their investigation for electrocatalytic CO2 reduction

We synthesize and investigate AuPd alloys for the electrocatalytic reduction of CO2. Thin films of AuPd were synthesized using an electron-beam co-deposition method, which yields uniform, phase-pure metal alloys with composition control. Scanning electron microscope images show that the thin films are relatively uniform and flat in morphology. X-ray diffraction showed alloying and phase homogeneity within the AuPd thin films. Elemental mapping of Au and Pd with scanning transmission electron microscopy shows that AuPd thin films are uniform in composition on the nanometer scale. X-ray photoelectron spectroscopy characterization indicates that AuPd alloys are slightly Au-rich on the surface and follow a similar trend to the bulk composition as determined by Vegards Law. CO2 reduction activity and selectivity were investigated across the AuPd system. All AuPd alloys were found to be more active and selective for formate production than either of the pure metals, indicating that Au and Pd can act synergistically to yield new electrocatalytic properties.

Dropping Out of Rural China's Secondary Schools: A Mixed-methods Analysis*

Students in rural China are dropping out of secondary school at troubling rates. While there is considerable quantitative research on this issue, no systematic effort has been made to assess the deeper reasons behind student decision making through a mixed-methods approach. This article seeks to explore the prevalence, correlates and potential reasons for rural dropout throughout the secondary education process. It brings together results from eight large-scale survey studies covering 24,931 rural secondary students across four provinces, as well as analysis of extensive interviews with 52 students from these same study sites. The results show that the cumulative dropout rate across all windows of secondary education may be as high as 63 per cent. Dropping out is significantly correlated with low academic performance, high opportunity cost, low socio-economic status and poor mental health. A model is developed to suggest that rural dropout is primarily driven by two mechanisms: rational cost-benefit analysis or impulsive, stress-induced decision making.

The Impact of Conditional Cash Transfers on the Matriculation of Junior High School Students into Rural China's High Schools

ABSTRACT The goal of this study is to examine whether promising a conditional cash transfer (conditional on matriculation) at the start of junior high school increases the rate at which disadvantaged students matriculate into high school. Based on a randomised controlled trial (RCT) involving 1418 disadvantaged (economically poor) students in rural China, we find that a CCT voucher has no effect on increasing high school matriculation for the average disadvantaged student. The CCT voucher also has no differential impact on students at any point in the distribution of baseline academic achievement. This result suggests that CCTs, while shown to be effective in many contexts, do not always work.

Trends and determinants of rural residential solid waste collection services in China

Purpose - The purpose of this paper is to describe the trends in residential solid waste collection (RSWC) services in rural China over the past decade and analyze the determinants of these services using nationally representative data. Design/methodology/approach - The authors draw on panel data from three rounds of village-level surveys of 101 villages. The three surveys were conducted in 2005, 2008, and 2012 in five provinces. The authors used fixed-effected regression approach to analyze the determinants of these services. Findings - The results show that in the aftermath of increased investment and policy attention at the national level, the proportion of villages providing RSWC services in rural China increased significantly from 1998 to 2011. However, half of all villages in rural China still did not provide RSWC services as of 2011. Based on econometrics analysis, the authors show that villages that are richer, more populous, and villages with more small hamlets are more likely to provide RSWC services. Originality/value - The analyses are based on primary survey data and the first to quantify trends in waste management services in the beginning of the twentieth century. The authors believe that the results will have significant policy implications for China in its continuing quest for better waste management policy.

Inequalities in the Pathway to College in China: When Do Students from Poor Areas Fall Behind?

Inequalities in college access are a major concern for policymakers in both developed and developing countries. Policymakers in China have largely tried to address these inequalities by helping disadvantaged students successfully transition from high school to college. However, they have paid less attention to the possibility that inequalities in college access may also arise earlier in the pathway to college. The purpose of this paper is to understand where inequalities emerge along the pathway to college in China, focusing on three major milestones after junior high. By analysing administrative data on over 300,000 students from one region of China, we find that the largest inequalities in college access emerge at the first post-compulsory milestone along the pathway to college: when students transition from junior high to high school. In particular, only 60 per cent of students from poor counties take the high school entrance exam (compared to nearly 100 per cent of students from non-poor counties). Furthermore, students from poor counties are about one and a half times less likely to attend academic high school and elite academic high school than students from non-poor counties.

Developing instruments to assess and compare the quality of engineering education: the case of China and Russia

Relatively little is known about differences in the quality of engineering education within and across countries because of the lack of valid instruments that allow for the assessment and comparison of engineering students’ skill gains. The purpose of our study is to develop and validate instruments that can be used to compare student skill gains in mathematics and physics courses in undergraduate engineering programmes across countries. The approach includes procedures to establish construct validity and other necessary psychometric properties. Drawing on data collected from over 24 engineering experts and 3600 engineering students across Russia and China, we establish that it is possible to develop valid, equitable and cross-nationally comparable instruments that can assess and compare skill gains.

Ability Tracking and Social Capital in China's Rural Secondary School System

The goal of this paper is describe and analyze the relationship between ability tracking and student social capital, in the context of poor students in developing countries. Drawing on the results from a longitudinal study among 1,436 poor students across 132 schools in rural China, we find a significant lack of interpersonal trust and confidence in public institutions among poor rural young adults. We also find that there is a strong correlation between ability tracking during junior high school and levels of social capital. The disparities might serve to further widen the gap between the relatively privileged students who are staying in school and the less privileged students who are dropping out of school. This result suggests that making high school accessible to more students would improve social capital in the general population.

Adult child migration and elderly parental health in rural China

Purpose - The purpose of this paper is to evaluate the effect of adult children migration on the health status of elderly parents. Increased labor migration in developing countries that lack adequate social security systems and institutionalized care for the elderly is a phenomenon that is important to understand. When their adult children go away to work, it is not clear what effect there will be on “left-behind” elderly parents. Design/methodology/approach - This study employs nearly nationally representative data from five provinces, 25 counties, 101 villages and 2,000 households, collected from two waves of data in 2007 and 2011. This sample comprises a subset of households which include both elderly individuals (above 60 years old) and their grown (working-aged) children in order to estimate the impact of adult child migration on the health of elderly parents in rural China. Findings - This study finds that adult child migration has a significant positive impact on the health of elderly family members. Practical implications - These findings are consistent with the explanation that migration raises family resources, which in turn may contribute to better health outcomes for elderly household members. Originality/value - This is the first paper to attempt to identify the relationship between household migration and the health of elderly parents within the Chinese context.

Irrigation investment in China: trends, correlates and impacts

Purpose - – The purpose of this paper is to describe trends in irrigation investment in China’s rural villages in the 2000s, identify the types of villages in which investment occurred and examine whether this investment had an impact on agricultural land. Design/methodology/approach - – This study makes use of longitudinal survey data from a nearly nationally representative sample of 101 villages spread across five provinces. The outcome variables are cultivated area, sown area and effectively irrigated area, and ordinary least squares regression and fixed effects models are used for the analysis. Findings - – In spite of sustained investments into irrigation from 1998 to 2011, there has been almost no impact on agricultural land. Cultivated area and sown area have fallen across all five sample provinces while effectively irrigated area remains largely unchanged. The authors also show that there is no relationship between investment into irrigation and agricultural land. Irrigation facilities also have the lowest rate of rural resident satisfaction of any of the major public services provided. Research limitations/implications - – More research is needed to understand the impact of irrigation investment on crop yields and water savings. Practical implications - – Policymakers may need to rethink the current pattern of investment into irrigation. Originality/value - – This is the first study to quantitatively model the impact of investment into irrigation at the village level all over China.

Improved CO2 reduction activity towards C2+ alcohols on a tandem gold on copper electrocatalyst

The discovery of materials for the electrochemical transformation of carbon dioxide into liquid fuels has the potential to impact large-scale storage of renewable energies and reduce carbon emissions. Here, we report the discovery of an electrocatalyst composed of gold nanoparticles on a polycrystalline copper foil (Au/Cu) that is highly active for CO2 reduction to alcohols. At low overpotentials, the Au/Cu electrocatalyst is over 100 times more selective for the formation of products containing C–C bonds versus methane or methanol, largely favouring the generation of alcohols over hydrocarbons. A combination of electrochemical testing and transport modelling supports the hypothesis that CO2 reduction on gold generates a high CO concentration on nearby copper, where CO is further reduced to alcohols such as ethanol and n-propanol under locally alkaline conditions. The bimetallic Au/Cu electrocatalyst exhibits synergistic activity and selectivity superior to gold, copper or AuCu alloys, and opens new possibilities for the development of CO2 reduction electrodes exploiting tandem catalysis mechanisms.The electrochemical transformation of CO2 into liquid fuels is a major challenge. Now, Jaramillo, Hahn and co-workers present a Au/Cu catalyst highly active to C2+ alcohols at low overpotentials as a result of a tandem mechanism where CO2 is reduced to CO on Au and further reduced to C2+ alcohols on nearby Cu.